Firefighter/EMT Sean Garrity (Steven Pasquale) - A young firefighter who is known for his dim-witted yet kind-hearted nature, but he is very intelligent and brave when it comes to the fire alarms. Garrity dons an EMT patch on his bunker jacket, hinting that he is EMT trained. It was revealed in a minisode that Garrity was the probie of 62 truck before 9/11. He begins a relationship with Tommy's sister Maggie in Season 3, ultimately marrying her despite her antagonistic personality (only to divorce later). It is heavily implied that he is sexually aroused by the female Gavins, because he not only married Maggie Gavin, he also revealed that he has masturbated while thinking about Janet (Tommy's wife) and Colleen (Tommy's daughter). In Season 4, Episode 6: "Balance," it is revealed that Sean's middle name is "Leslie" in honor of his late aunt. In Season 5, subsequent back problems ultimately lead to the revelation that Sean has developed renal carcinoma (kidney cancer), most likely 9/11-related. In fear that he will be discharged from the FDNY if he uses the department insurance, Sean skims off the bar profits to pay medical expenses. He has since recovered. In season 7, he develops a romantic relationship with a woman that turns out to be a post-coital flatulater, as Sean smells a terrible stench after their moments of sex. Sean asks her to marry him and she says yes. After the big fire at the end of the series, Sean puts in a transfer request. But after Lou's postmortem letter that requests that the crew stays together, Sean stays with 62 Truck. Sean's rank is also a Firefighter, 1st Class in the New York City Fire Department's Ladder Company 62. He has over 12 years on the job and is also a certified New York State Certified First Responder with Defibrillator(CFR-D) and an Emergency Medical Technician(EMT).
Firefighter Mike Silletti (Mike Lombardi) - A former probationary firefighter who at the beginning of the series had just begun his probationary period, and as such was regularly referred to as "Probie" until later in the series. Emotionally needy and at times emotionally unstable, Mike often finds himself involved in a variety of sexual situations (often involving homosexuality in some shape or form) over the course of the series before ultimately coming out as bisexual, with a preference towards women. Mike also suffers from dyslexia and is considered to be slow-witted by the rest of the firehouse, even more so than Garrity. In the fifth season, he starts a band called Apache Stone (also the name of Lombardi's real life band). The band is a hit and Mike thinks about leaving the FDNY to pursue a career in music, until the rest of his band is offered a record deal if they dump him, so he gives up on the career in music and remains a firefighter. In season 7, he helps Colleen and Black Shawn with planning their wedding and is finding his true calling in wedding planning. After the big fire at the end of the series, Mike puts in a transfer request. But after Lou's postmortem letter that requests that the crew stays together, Mike stays with 62 Truck. On the way to Lou's memorial service, Mike opens up Lou's ash box. When Franco and Black Shawn open up the windows after being berated by Tommy to spit out their gum, the open windows cause a vortex, blowing Lou's ashes all over the inside of Tommy's truck. Mike's rank is also a Firefighter, 1st Class in the New York City Fire Department's Ladder Company 62. He has over 7 years on the job, and began his career in 62 Truck.
Firefighter/EMT Bart "Black Shawn" Johnston (Larenz Tate) - Initially a probationary firefighter recruited for his basketball talent in order to beat a rival firehouse and as such, negotiated with the rest of the firefighters that they could not call him "Probie" nor do any other rookie hazing stuff. The firefighters (minus Tommy) indulge Black Shawn's demands (including his request that they call him "Shawn" instead of Bart, despite the fact that there is another Sean in the firehouse), creating tension between Tommy and Black Shawn. However, by the end of season four, Tommy begins to respect Black Shawn after seeing him in action during a fire, confirming that Black Shawn was a good fireman and not a prima donna. He is engaged to Tommy's daughter, Colleen, but may want to break it off because he is intimidated by her sexual prowess. However, he has realized that he really loves her and wants to be with her. At the start of season six, Black Shawn starts to think more into the future about his relationship with Colleen, especially as she develops an alcohol addiction. Black Shawn keeps in communication with Tommy over his fears of her addiction. In season 7 Shawn and Colleen are engaged. In the episode "Vows" Shawn and Colleen get married. After a large fire that claims Lou's life, Shawn decides to resign from the FDNY in fear for Colleen. But when Tommy returns to active duty, Shawn returns in confidence that he will be in good hands next to his Father-in-law. Black Shawn's rank is a Firefighter, 1st Class in the New York City Fire Department's Ladder Company 62. He has over 5 years on the job. He is a certified Emergency Medical Technician (EMT).
Probationary Firefighter Damien Keefe (Michael Zegen) - The son of Jimmy and Sheila Keefe and Tommy's nephew/godson. Much to his mother's dismay, he decides to become a firefighter like his father and late in season 5 he becomes a full-fledged "probie" and is assigned to the same house his uncle works at. Being young and inexperienced, he has often gotten into trouble either by using poor judgment or saying the wrong things at the wrong time. Damien was also described as being a "momma's boy," remaining loyal to his mother even to the point of helping her in the love triangle between her, Tommy and Janet—much to Tommy's annoyance and Damien's enjoyment. Nevertheless, his kind heartedness, boyish looks, hard work and determination to be a good firefighter make up for his flaws. When not firefighting Damien played guitar for Silletti's band Apache Stone. In Season 5, the band is offered a record deal, but only if they drop Silletti as their vocalist. In Season 6, Damien begins to consider leaving the firehouse at the behest of his uncle Mickey and his mother. He also strikes up a relationship with Penny, a female firefighter from another truck. Damien eventually makes up his mind to stay, and that night they respond to a warehouse fire in which Damien is crushed by a falling tablesaw and other debris. It is later revealed that he survived, although he is severely brain-damaged and uses a wheelchair. Tommy and Sheila are Damien's caretakers. In season 7 it is revealed that Damien is getting a little bit better as he barely responded to Lou once when Lou came over to read Sheila the letter that Tommy wrote her. Even after the accident, Damien is still considered a member of 62 Truck. Damien's rank was a Probationary Firefighter in the New York City Fire Department's Ladder Company 62.
Firefighter Chauffeur Niels Jorgensen (Niels Jorgensen) - Neils is the assigned Ladder Company Chauffeur, or driver of 62 Truck, on the same shift, or platoon as Tommy, Lou, Shawn, Franco, Mike, and Garrity. Not much is known about Niels, but he seems to be well liked by the crew. His character was gradually expanded into a supporting role over the course of the fifth season. He seems to be a sensitive man, as in one episode he is seen crying after accidentally running over a cat with the fire truck. In the show, Neils has the rank of Firefighter, 1st Class in the New York City Fire Department's Ladder Company 62. This character is played by real life Lieutenant Niels Jorgensen of the FDNY.
Probationary Firefighter Joe "Husky" Coots (Joe Coots) - The probationary firefighter Tommy berated and yelled in his face for laughing at a part of his speech. Lou insisted that Tommy gets him in 62 Truck as Lou's replacement for cooking, because Lou suggested he knew his way around food and would be a better cook than a firefighter, although the firefighter part, the crew would take care of.
Battalion Chief William "Needles" Nelson (Adam Ferrara) - A young FDNY Battalion Chief swiftly promoted due to the loss of the 343 firemen during 9/11. Became interim chief of the house when Jerry Reilly was in the hospital, and eventually took over his job permanently upon Reilly's inability to return to active duty and his subsequent suicide. Unlike Reilly, Nelson is a little more soft-spoken, and is willing to get in the face of Chief Feinberg when necessary. Up until recently, he was very down-to-earth with the other firefighters. But Season 5 finds him becoming more strict, partly due to Franco's beliefs as well as his own belief that the firefighters aren't respecting him enough. Needles is also married to a Russian Mail-order bride and seems to be unable to control her hard partying ways, which could land him in prison for marrying an illegal alien and get her deported back to Russia. Seen in only a few episodes and known primarily as "Mrs. Needles" (but later revealed to be named Snezyana), no one fully knows the extent of Needles' and his "wife's" affection or relationship. In a Season 5 episode "Lesbos", after Tommy and the boys bring back a severely drunk Mrs. Needles, Needles shows that he cares about his wife and tends to her—despite the fact that she had made out with two women and gave oral sex to Derek. (Needles does not know about the latter, due to the kindness of the entire crews' heart.) Needles uses leverage in Season 6 to save the firehouse. Despite Needles' disagreement with Tommy's firefighting ethics and always putting the spotlight on Tommy every time something goes wrong and Needles gets reprimanded by FDNY headquarters, Needles and Tommy share a mutual respect toward each other due to them serving in the probie academy together.
Deputy Chief Sidney Feinberg (Jerry Adler) - A second generation FDNY chief who does not like to be called Chief Feinberg in honor of his father. Deputy Chief Feinberg is Jewish and likes to play by the books. Feinberg does not respect Needles much as a Chief because Needles was quickly promoted after 9/11. Tommy's rogue attitude upsets him, yet he still wants to set up his daughter, Beth, with him. Whether Tommy does not call his unbalanced daughter back or tries to go further with her, Feinberg is offended either way. After finding out that Tommy has been fighting fires undercover in his spare time (wearing his cousin's old uniform), Feinberg writes him up for a Section 8. Although Tommy is cleared of the Section 8, he hasn't been cleared of turbulence with Feinberg. But Tommy and Feinberg resolves their differences later on. Feinberg runs afoul of his crew in season 6, when he seems to stand by and let the house get shut down, leaving Needles to save it. In Season 7, it is hinted that Feinberg is developing into the early stages of Alzheimers. After visiting Ground Zero with Tommy, Needles, and Lou, Feinberg reveals his feelings about 9/11 by writing letters to his loved ones and all the past guys he worked with or was in charge of. This was what inspired Tommy to write the letters also with Lou writing his Posthumous letter. Feinberg is a Vietnam Veteran.
Lieutenant Franco Rivera (Daniel Sunjata) - One of the most skilled and reliable members of the crew. Franco is of Puerto Rican/Mexican descent. Franco is Tommy's former protégé with the main group of firefighters. As the resident ladies' man of 62 Truck, he finds out in Season 1 that he has a 5-year old daughter named Keela, whose mother died of a cocaine overdose in a nightclub. In the Season finale, Franco gets injured after a ceiling collapses over top of him, while trying to help a disoriented Tommy. This causes conflict between Tommy and Franco in the beginning of Season 2 which was eventually solved when Tommy transferred back to 62 Truck. While he was injured, fellow firefighter Laura Miles helps Franco with Keela. This leads to a romantic relationship between the two. When Franco and Laura break up later in the season, Laura quietly transfers out of 62 Truck, causing Franco's emotional breakdown in front of her old apartment. In Season 3, Franco loses custody of Keela to a wealthy former girlfriend (Susan Sarandon) when she finds out that he had custody of Keela despite signing away his parental rights. In Season 5, he is revealed as one who believes that 9/11 was an inside job, which causes controversy inside and outside the firehouse. This also led to a physical confrontation between 62 Truck and a bunch of other firefighters from different firehouses. After Needles and Lou see Franco in the basement pounding on a punching bag, they recruit Franco for the department's underground boxing organization. During this time, he starts dating a fellow female boxer who later turns out to be a lesbian. In Season 6, Franco helps out Janet with the kids and around the house while Tommy is hospitalized after Teddy Gavin shot him. Franco becomes close to Janet to the point where the two almost kiss. This leads to conflicts with both Tommy and "Black Shawn", with Franco and Shawn having a physical altercation. In Season 7, Franco is a little more fearless and outspoken towards his fellow firemen, including his superiors. As Lou's health is failing, Tommy is suspended for cursing on national television, and Chief Needles appears to be doing nothing to change things, Franco steps up and suggests he would be a better leader. After one more disagreement between Lou and Franco, Lou (out of anger) suggests that Needles appoint Franco to Acting Lieutenant. Even though Franco has the house cleaned and well-organized, he shows poor judgment during a call. Lou tells Franco that he's not ready to wear the lieutenant's shirt, and Franco's temporary leadership role ends. Despite this, Franco passes the Lieutenant's exam, and waits for his new assignment. After Lou dies in an arson fire, Tommy is initially promoted to Lieutenant but then resigns from active duty. Franco takes over the Lieutenant's post permanently, much to Tommy's respect as the two salute each other at the end of the series. Franco's final moment in the series is drilling the newly graduated probationary firefighters, shortly after Tommy gives them a speech about life lessons after 9/11.
Deputy Chief Ron Perolli (Michael Mulheren) - Perolli is seen by the other firefighters in the house as a "pencil pusher" and an unlikable boss. Replaced by nobody specifically, he made his last appearance in the season 3 episode "Retards". Perolli had a poor relationship with Tommy, mostly due to Tommy's alcoholism and what Perolli called Tommy's "dangerous tactics". As an administrator he was involved in Chief Reilly's incident with a gay ex-firefighter, Lou's incident with Laura, and Mike's transfer request.
Battalion Chief Pecher (Peter Tolan) - Peter Tolan, the creator of Rescue Me, made a guest appearance in Season 3 as a Battalion Chief, who temporarily replaces Jerry after his heart attack. The crew makes his last name, Pecher, the butt of their jokes, pronouncing it as "pecker". In actuality, it is pronounced "Cher with a puh," according to Pecher. Pecher's conversations are not popular with the crew as he talks about propane and biology.
Battalion Chief "Izzy" (Phil Esposito) - He is introduced in Season 3 during a dry land hockey game between Tommy's crew and Izzy's crew. He is also at Battalion Chief Jerry Reilly's house when he is discovered after his heart attack. He eventually takes over as head coach of the FDNY hockey team, much to Tommy's dismay, as it is known that Izzy and Tommy don't get along very well. Izzy is played by retired NHL hockey player, Phil Esposito.
Firefighter Laura Miles (Diane Farr) - A female firefighter who replaced Billy Warren at the end of season one and for the rest of season two. Initially rejected by most of the crew simply for being female, she slowly gains their respect and ultimately begins a romantic relationship with Franco. Unfortunately, when her relationship with Franco ends, she secretly transfers to a different firehouse and instructs her friends not to share any information regarding her whereabouts with her former lover or crew. Laura was not seen again on the series.
Firefighter Mark "Sully" Sullivan (Lee Tergesen) - Tommy's replacement during the first three episodes of Season 2, when Tommy was relocated to a firehouse on Staten Island. Initially very popular because he was personable and an outstanding cook, Sully requested a transfer out when the crew rescued him from a burning sex club to find out that he was a cross-dresser who was very much into BDSM. After his transfer, Lou sarcastically suggested "lighter on the mascara." Sully was not seen by 62 Truck after the embarrassment.
Lieutenant Kenneth "Lou" Shea (John Scurti) - Affectionately called "Lou" on account of his rank, he is among the smartest of the crew as well as the resident "philosopher" of the group. Lou is known as the "King of The One Liners" for his sarcasm. Divorced by his wife in season one and conned out of his life savings by a prostitute in season two, "Lou" recovers by the end of the third season with help from Tommy. He has a fondness for writing poetry, which is often not-so-gently mocked by the firefighters in the house. In Season 6, he suffers a heart attack, which leads the doctor who performs FDNY's physical exams to tell him that he can no longer actively fight fires. As the season ends, Lou is trying to make a deal with the doctor to falsify the exam results. In Season 7, the other firefighters wear Lou's shirt and take his various physical and mental exams for him. After one more disagreement between Lou and Franco, Lou suggests that Franco be appointed to Acting Lieutenant which Needles makes the decision as House Chief to do so. After Franco gets to be demanding and micromanaging even in the field after a poor judgement call, Lou demotes Franco back to his regular firefighter status. In a devastating five alarm fire, Lou perishes. Some of Lou's ashes were sent in the ocean while the rest ended up on his comrades who were trying to transport his ashes (his ashes were mixed with Duncan Hines Red Velvet cake mix). After Tommy's epic and familiar speech with the probies, Lou's spirit shows up once more to talk to Tommy one last time.
Battalion Chief Jerry Reilly (Jack McGee) - Jerry Reilly was the chief of the 15th Battalion, quartered at the same firehouse as Ladder 62 and Engine 99 at the start of the series. Most of Jerry's storylines revolved around his dealing with his gambling addiction, his Alzheimer's-ridden wife, and the problems he had accepting his son's homosexuality. After suffering a heart attack, he was told he would have to retire from active duty and take a desk job. Though outwardly cheerful and accepting of this new stage of life— even making plans for the next day—he went home and took his own life rather than face life without fighting fires. Chief Reilly was very well respected by his crew even in death when his death is ruled as heart failure instead of suicide.
Firefighter Billy Warren (Ed Sullivan) - A redshirt character who died in a fire after saving Tommy in season 1. Despite his detached and possibly psychotic behavior; he was well liked by the rest of the crew, and he knew every building layout in the city. It was revealed in the pilot episode that Billy may have been diagnosed with prostate cancer, which may explain his behavior and outlook on life. He was very popular with women and, as was revealed by his widow after his funeral, had a 10-inch penis, winning him an in-house contest over who had the largest penis. He appears as one of Tommy's "ghosts" during season two, three, and four, condemning Tommy over his various actions, and shows up again in season five with all of the other ghosts when Tommy starts drinking again.
Senior Firefighter James "Jimmy" Xavier Keefe (James McCaffrey) - Jimmy Keefe is Tommy's cousin and best friend who died at Ground Zero on 9/11 in the collapse of 2 World Trade Center. Only his finger was found in the rubble. Jimmy was the husband of Sheila and the father of Damien. Like Sean Garrity, Jimmy Keefe was EMT trained. His ghost often haunts Tommy, particularly when Tommy has been drinking. In the first season, Tommy and Jimmy postmortem were still old pals, but after Jimmy caught Tommy sleeping with Sheila, their relationship was filled with more hatred. Jimmy Keefe was considered an honorable hero to a lot of firefighters in the FDNY. He was assigned to FDNY Ladder Co. 71 prior to being assigned to Ladder Co. 62.
Firefighter Vito Costello - One of four firefighters from Ladder Co. 62 who were killed on 9/11.
Firefighter Ricky Davis - One of four firefighters from Ladder Co. 62 who were killed on 9/11.
Firefighter Bobby Vincent (Anthony Mangano) - One of four firefighters from Ladder Co. 62 who were killed on 9/11.
Janet Gavin (Andrea Roth) - Janet Gavin is Tommy Gavin's estranged, overdemanding wife. She has two daughters (Colleen and Katy) and two sons (Connor and Shea) with Tommy, plus one son (Wyatt) who is most likely the product of an affair with Tommy's brother, Johnny. Over the years, she has had a complicated love-hate relationship with Tommy that exploded after 9/11 and led to their separation and impending divorce. At the end of season one she leaves Tommy, taking the kids after Tommy destroys her relationship with a new boyfriend, but she comes back to Tommy after he kidnaps their children from her. With the aid of anti-depressants, the two reconcile but separate again after the death of their son, Connor, who died in a hit-and-run accident by a drunk driver. She then became involved with Tommy's brother, Johnny Gavin, but was raped by Tommy during a meeting to discuss their impending divorce. She isn't angered by the rape, and in fact returns to Tommy later on and seduces him. Between Seasons 3 and 4, she gave birth to a boy who, after months of delay, is named Wyatt. She is uncertain of the paternity of the baby, but the boy's dark hair leads her and Tommy to believe it is Johnny's. During a separation in Season 5, Janet has a live-in boyfriend, Dwight, who is confined to a wheelchair and who constantly antagonizes Tommy. In the Season 5 finale, Janet files for divorce, but it is hinted she is only doing so to get Tommy to come back to her. In Season 6, Tommy and Janet decide to give their relationship one final shot, so long as Tommy gives up drinking permanently (which he does) and does not have contact with Sheila again. But Janet ends up relenting on the latter condition when Sheila's son, Damien, is horribly injured in a fire, allowing Tommy to help Sheila take care of Damien. The Season 6 finale reveals that she is pregnant again. In Season 7, Janet is demanding that Tommy retire from active duty in the FDNY for the sake of their unborn child, much to Tommy's chagrin. But after their son, Shea, is born in their apartment, Janet convinces Tommy to stay with 62 Truck.
Colleen Gavin-Johnston (Natalie Distler) - Tommy's rebellious teenage daughter (the first 3 seasons) who often pits her parents against each other. In season one she dates Sean Murphy and gets his initials tattooed near her iliac crest, much to the dismay of Janet and Tommy. While on their way to a concert, Colleen and Sean are involved in a car accident which Tommy and his fire crew attend. Tommy plots to break them up by hiding all the get-well gifts Sean sends her. Later on Colleen gets in trouble at school for making out with her new girlfriend after she openly announces to her parents that she is a lesbian. Tommy was surprisingly supportive of Colleen's tenure as a lesbian, figuring it would at least keep her away from men who are just looking for sex. After her younger brother Connor dies, Colleen finds Jesus. Her finding salvation, however, has more to do with her wanting to fit in and be popular and not really from a deep need for spirituality. By the fourth season her love for Jesus seems to have passed. According to the season 4 premiere Colleen had gone back to lesbianism briefly (during the 9 months between seasons 3 and 4), but now she is dating a 26-year-old man who is the lead singer of his band. Tommy has tried to break the two of them up, but relented, even giving Colleen a credit card so she could at least live comfortably. Her boyfriend uses it to buy an engagement ring for another girl, which actually thrills Tommy. She then starts a relationship with Black Shawn. They plan on waiting until they are married to have sex, but Tommy tells Colleen that they should just have sex, thinking it will reduce the chances of her marrying Shawn. Colleen and Shawn even decide to move in together later in Season 5, and despite all of Tommy's reservations about the relationship, Colleen truly loves Shawn. In the Season 6 premiere, Colleen is now 21. It is also revealed that she is becoming addicted to alcohol just like her father. However, Tommy uses radical techniques such as dunking her head in alcohol to get her to stop, which worked. For a while Tommy became her AA sponsor, but due to him constantly juggling work, his family and helping Sheila take care of Damien, he misses her AA meetings and she calls Teddy to take over as her sponsor. At the start of Season 7, Black Shawn proposes to Colleen, she accepts, and celebrates by getting so drunk that she passes out. Throughout season seven she is in pursuit of the perfect wedding, with the help of Mike. In the episode "Vows" Colleen and Shawn get married.
Katy Gavin (Olivia Crocicchia) - Katy is Tommy and Janet's younger daughter. Like her siblings, her love is usually for sale depending on which parent pays the most. After the death of her brother Connor, Katy was for a brief time withdrawn and existential. Her dark outlook on life and lack of belief in God scared Sean Garrity. Currently, she's attending an all-girls private school somewhere in upstate New York and has shown embarrassment for the type of parents Tommy and Janet have been. During season 5 Katy's relationship with Tommy seemed to have improved, with Katy even going as far as telling him how proud she is that he stopped drinking — unknown to her, Tommy has relapsed and has continued drinking. Katy has also seemed to be having disciplinary troubles at her school and has since been living with her mother. In the season 5 finale, Katy has decided she has had enough of her mother and moves in with her big sister and Black Shawn. In season 7 she is seen living with her mother and father again.
Connor Gavin (Trevor Heins) - Connor was Tommy's second-oldest child and first son. Connor was killed by a drunk driver in the 12th episode of the second season. Shortly before he died Connor eavesdropped on a conversation between Tommy and Damien where Tommy explained why he loved his job. Connor told his mother he was going to grow up to be a fireman because it was in his blood. Janet and Tommy both took Connor's death hard. Janet blamed Connor's death on Tommy and began sleeping with Tommy's brother Johnny. Tommy's uncle Teddy murdered the drunk driver (due to the fact the man got off previously for another drunk driving death due to connections and it was feared he would again) and went to prison. Older versions of Connor (David Call) have appeared in Tommy's hallucinations as of late; once as a junkie robbing their bar, and again as a successful Wall Street businessman.
Wyatt Gavin - Janet's second son (born between Seasons 3 and 4) and a major source of conflict in Season 4. There is a question of paternity, as Janet was sleeping with Johnny Gavin and Tommy Gavin, meaning either could be the father, but once the baby grew black hair, it is assumed that he is Johnny's son. A paternity test has not been administered to Tommy or Johnny, Johnny because he was killed on the job before Wyatt was born. Janet initially does not name the baby and believes that he hates her, since he cries whenever she picks him up but will stop as soon as she hands him to someone else. The one time he didn't cry in Janet's arms was when she was yelling at Tommy, prompting him to tell her to "criticize me some more." No-Name is hated by Katy due to his constant crying, which also drives Janet into depression, making her unable to care for the baby or Katy. This prompts Tommy to consider giving the baby to Sheila, whom No-Name seems to like. However, Johnny comes to Tommy in a vision and says that will create a future of confusion and trouble for No-Name and everyone else, as the baby has already caused much chaos to people's lives as only an infant. Johnny suggests that Tommy kill the baby for its own good, but Tommy refuses and instead gives him to Sheila. Janet and Katy soon steal the baby right back. Sheila wants to name the baby "Elvis" and Janet wants to name him "Wyatt." (Tommy hates both names.) In the Season 4 finale, the baby finally smiles in Janet's arms. In the first episode of Season 5, it is confirmed that the baby remained with Janet and has been named Wyatt.
Shea Gavin - Tommy and Janet's youngest son, named after deceased firefighter Kenneth Shea. Shea was born in the Gavins' household, with Tommy delivering him. Tommy passed out after delivering Shea. Tommy first called him "Lou" before Janet revealed that she always hated the name Lou. At the end of the series when Lou's ghost shows up once more, Lou stated that Shea Gavin was a great name for a restaurant. Tommy said "or a quarterback."
Michael Gavin (Charles Durning) - Michael Gavin (full name Michael James Gavin) was Tommy's eccentric father. A retired firefighter, he decided to "live life" while he has some time left. During Season 2 he took a spontaneous vacation and came back married to a rich Korean woman, Jenny Ng, with a penthouse full of cats. After her death, he expected to receive a windfall inheritance, but it didn't happen. Michael seems to have issues with his daughters. For example, he has a very rocky relationship with Maggie, whom he hadn't spoken to in years, and disowned his other daughter Rosemary, for reasons unknown (but likely because he was ashamed of having a deaf daughter). Attending a baseball game with Tommy, he dies in the season four finale. Michael Gavin has appeared in a few later episodes as one of Tommy's ghostly apparitions.
Martha Gavin (unseen character) - Tommy's mother. She died in the first season, coincidentally not long after Tommy used her grave illness as an excuse to try to get out of a traffic ticket. Indications point to a less-than-loving marriage between the Gavins towards the end, and Janet Gavin had very little good to say about her at her funeral, as all she did during the wake was berate Tommy by questioning about him and Sheila.
Jenny Ng (Ching Valdes-Aran) - Michael Gavin's second wife and Korean national. Everyone in the Gavin family by mistake called her Jenny "Nig" instead of "Ng". Mrs. Ng was a cat lover as she had 40 or more cats in her Park Avenue penthouse. Ms Ng later in season 2 died of a heart attack in her dining room. Tommy, Michael, and Teddy found her with her face half devoured by the cats. Soon after, The Gavins got excited because Mr. Gavin was supposed to get Ms Ng's inheritance. But most of it by her request went to her cats, while Mr. Gavin only received 50 grand.
Johnny Gavin (Dean Winters) (2004–2007, 2009, 2011) - Johnny Gavin is Tommy's younger brother. He is a well-connected detective in the NYPD, who reluctantly helps Tommy out in terms of getting him out of trouble with the law and providing information to Tommy when asked. He has an ex-wife named Angie (Marisa Tomei) and two daughters, who have not been seen in the series. It is mentioned that one of the daughters is in reform school. During the first season, Johnny helps Tommy (Denis Leary), mess with Janet's new boyfriend by having him arrested at one point. Johnny encourages Tommy to call their father, Michael Gavin (Charles Durning), especially after Michael separated from their mother. Eventually, Michael returned home, but she died shortly after. Johnny also attempts to help Tommy locate Janet and Tommy's kids when she moves them out of New York at the end of the first season. As the show progressed, the character becomes more and more openly resentful towards Tommy and having to clean up his brother's messes, which is coupled with the fact that Johnny has been carrying an unrequited crush for Janet for years. After a short-lived reconciliation between Tommy and Janet, their only son Connor was killed by a drunk driver. Janet (Andrea Roth) moved out with their two daughters at the end of the second season. At the request of Tommy, Johnny began to look after Janet. The two started an affair, which was revealed at the end of the first episode of the third season. Tommy subsequently found out about the relationship and delivered a brutal beating to his brother at their father's 83rd birthday party. Johnny eventually reveals to Tommy that Janet is pregnant, but he has no idea that Janet has cheated on him with Tommy. Towards the end of his life, Johnny admits to Tommy, via voicemail, his regret over the affair with Janet and the subsequent hurt he caused his brother. Soon after, Johnny is shot three times in the back during a stakeout and is killed. This incident devastates Tommy, who had not yet reconciled with Johnny, but eventually was able to forgive him postmortem. Tommy has had visions of Johnny's ghost in the Seasons 4, 5 and 7 several times. Johnny was a recurring character in the first two seasons before becoming a regular in the third season.
Angie Gavin (Marisa Tomei) (2006) - An ex-wife to Tommy's brother Johnny. Tommy and Angie recently came into contact with each other and started going out on dates to try to make Janet and Johnny jealous. They found out they have feelings for each other and started to have sex regularly. Tommy, however, could not climax. Angie found out that he still thinks about Janet, and when Angie wanted to have sex in his bed (in Janet and Tommy's old room), Tommy would not do it. At that moment, Janet showed up in a trench coat with lingerie underneath, ready to have sex with Tommy. Angie got even angrier and more insulted, so she left. As they all walked out of the apartment, Angie's former boyfriend, Sebastian, who has subsequently been stalking Angie for days, escorts her out. He then kicks Tommy in the face. Angie and Janet both leave very angrily, leaving Tommy on the floor of the hallway, bleeding from the lip. Angie and Johnny have two daughters who were never introduced.
Maggie Gavin Garrity (Tatum O'Neal) - Born Margaret Sue Gavin, Maggie was known as "Peggy Sue" when she was younger. She is Tommy's older sister who returned to the area after learning that their father was supposed to inherit money from his recently deceased wife. She is resented by her father for reasons that have not yet been revealed; she is a heavy smoker and drinker, and is considered to be evil incarnate by Tommy and the rest of her family (a charge Maggie makes no attempt to deny and revels in). She began a relationship with Sean Garrity, a member of Tommy's fire crew, but secretly dated four other men behind Sean's back. When Sean found out and confronted her about it, his assertiveness led to her dropping her other lovers for Sean. The two became engaged, though it fell apart when Sean realized that he could not physically handle being married to someone as openly vile as Maggie, a move that caused Maggie to finally break down into tears. Maggie and Sean get back together during Johnny's funeral, and pay the priest $500 to marry them in the cemetery. Later during the fourth season, she and Sean divorce. Maggie appears to be addicted to pornography. She has been seen in later seasons alternately drinking or attending AA functions with her extended family.
Timo Gavin (James Badge Dale) - Timo Gavin is Tommy's much younger brother and also a cop. Only seen during the first season, but is mentioned in later seasons.
Rosemary Gavin (Deanne Bray) - Rosemary Gavin is Tommy's sister. She was born deaf and it was revealed in Season 1 that she was "sent away" as a child. She returned during the funeral for Johnny Gavin in Season 3, but was not seen again.
Father Liam Murphy (Christopher Durham) (2005) - Tommy's illegitimatehalf-brother, the result of an affair Michael Gavin had with a woman (unnamed) 36 years ago. Liam is a priest and it's eventually revealed that he was molested as a child and has himself become a pedophile. Tommy, Mickey, and Johnny confront him and he's arrested.
Mariel Murphy (Noelle Beck) - Liam has a sister, Mariel, whose mother is unclear on her paternity. Both Tommy and Johnny are attracted to her, but after a test it's determined that she is not the daughter of Michael (and thus not their sister) Tommy still decides not to pursue a relationship with her. Mariel is last seen at Connor's funeral wake.
Sheila Keefe (Callie Thorne) - Sheila Keefe is the needy, sexy, foulmouthed Italian/Irish-American widow of Jimmy Keefe, and the mother of Damian Keefe. She has a stormy relationship with Tommy. She is now quite wealthy after receiving both an inheritance and an insurance settlement when her house on Long Island burned down. When Damien becomes a firefighter, she jumps on her mother ship numerous times and always gets in Tommy's face about it, despite Tommy having Damien assigned to 62 Truck. She is helped by Tommy to take care of a now brain-damaged Damien after he survived his accident at the warehouse fire. In Season 7, she finally accepts that Damien is never going to walk again. She opts to pay for Colleen and Black Shawn's wedding because she wants to give Colleen the wedding she can never give Damien. She started a relationship with Tommy's cousin, Mickey, in Season 6 which was short-lived because he refused to coddle Sheila when she was spending large sums of money on futile treatments for Damien. But after Colleen and Shawn's wedding, the two rekindle their relationship.
Mickey Gavin (Robert John Burke) - Tommy's cousin, Alcoholics Anonymous sponsor, and defrocked priest. The whole story of why Mickey left the Church has never been fully explored, but the fact that he had a girlfriend while he was supposed to be celibate might be part of the reason. Although in episode 7 of season 2, Mickey suggests to Tommy that the reason he left the priesthood (assumed willingly) was the Church's handling of priest pedophilia. He begins a relationship with Sheila in Season 6 but leaves her sometime after Damien's accident when he confronted her about all the money she was spending on treatments that were not working, not wanting her to end up poor and hopeless. However, in Season 7, Mickey and Sheila decide to give their relationship another chance, after Sheila finally accepts the fact that Damien will not get any better.
Eddie Gavin (Terry Serpico) - Tommy's cousin who is a lawyer. He often helps Tommy and the family with legal issues. He frequently clashes with Tommy, and gets into arguments with him, which occasionally escalate into mutual shoving and slapping attacks. He is an alcoholic, albeit in denial, and attends the "Gavin family AA meetings". In Season 6, it is revealed that he now owns the bar that Tommy was shot in. Because of issues with him being a lawyer, however, it is revealed at the start of Season 7 that he had to sell the bar to Teddy and Mickey.
Teddy Gavin (Lenny Clarke) - Teddy is the younger brother of Michael Gavin and uncle to Tommy. Teddy made a lot of money from gambling, but made even more from modelling for a men's sportsmagazine. Ironically, he mistakes the man who hires him as a model for a loan shark that has come to "collect" on his gambling debts. Although Teddy considers himself a heterosexual, he received oral sex from a transvestite (which he discovered after the fact), and wasn't overly disturbed by sexual advances from a black dwarf. Teddy is arrested at the end of season 2 for the unlawful killing of the drunk driver that had killed Tommy's only son, Connor Gavin. Teddy was upbeat about his arrest, and accepted the consequences of his actions. During season 3, Teddy appears to be enjoying his time in prison, and asked that no one try to convince the courts to lessen his sentence. Teddy marries a woman named Ellie in order to become eligible for conjugal visits. Although things worked out at first, Ellie becomes too emotional and is often too upset to sleep with Teddy after Johnny Gavin died. Ellie has a history of becoming attached to prisoners and leaving them after they are released from jail. Teddy sees this as a way to get rid of her, and desperately seeks to be released. During the second episode of season 4, Teddy is found not guilty of murder and is released from prison. He assumes Ellie will leave him, however, she surprisingly wishes to commit to him. Teddy then lies about having to use the restroom and escapes through the window. He then hides out in the home of one of the officers who worked at the prison, before Ellie finds him and confronts him. Despite Teddy's attempts, the two stay together and eventually appear to be a reasonably happy couple. At the end of season 5, Teddy loses his wife Ellie to a drunk driving accident, blames Tommy, and returns to Tommy's bar and shoots him twice, leaving him dying. He later serves as Colleen's AA sponsor, after Tommy repeatedly misses Colleen's meetings. Teddy and his nephew Mickey take over the bar in season 7. But after Tommy discovers Colleen drunk in the back storeroom, Tommy shoots and blows away all the booze on the shelves, finally putting the bar out of business. Teddy walked Colleen down the aisle under Colleen's request, as Colleen insisted Tommy would never make it down the aisle without passing out.
Ellie (Patti D'Arbanville) - A woman who loved how Uncle Teddy killed Connor's killer and so she wrote him love letters. Teddy married her while in prison, making him eligible for conjugal visits. A prison guard tells Teddy that Ellie is only interested in him because she knows that he can't cheat on her if he's in a prison, and if ever he gets out, the relationship will fail. Eventually, Ellie becomes too much of an actual wife, complaining about the decor of the conjugal visit trailer and getting upset when Teddy does not ask her about her day. After Johnny's death, she was too upset (although she never knew Johnny very well) and didn't want to sleep with Teddy. Due to these changes, Teddy wanted to get out of prison so he can ditch her. When Teddy was freed after his appeal trial, Ellie declared that she truly loved him and didn't want to leave him. Teddy, horrified that he is a married man, ditches her at a coffee shop. She finds him at the prison guard's home and makes him attend AA meetings, believing alcohol is the only thing standing between them. The two get back together, but after the Gavins (as a family) return to drinking, Ellie becomes the victim of a fatal car crash at the end of the fifth season.
Peg Gavin - Teddy's first wife. She leaves Teddy. Teddy says she turned out to be a lesbian.
Uncle Teddy's children - Teddy tells Tommy his kids are "assholes" in season one.
Johnny and Angie Gavin's two daughters - One is in reform school according to Tommy.
Mickey's parents - Presumably Mickey and Tommy's fathers are brothers.
Eddie's parents - Presumably Eddie and Tommy's fathers are brothers.
Jimmy's parents (as well as Tommy's aunt and uncle) - It Is Stated by Sheila that Jimmy's father died in a fire. Presumably, Tommy's father and Jimmy's mother are siblings.
Jimmy's two sisters - Jimmy slept in the same room with them growing up.
Anne Marie Gavin - Presumably an unseen sister of Tommy's. Mr. Gavin called her when he returned from his trip to Ireland according to Johnny. Presumably this wasn't just another name for Maggie or Rosemary. Neither had spoken to Mr. Gavin in years.
Firefighter Peter Reilly (Neal Jones) - The gay son of Jerry Reilly, a Boston firefighter, who in Season 1 testified to Jerry's character in court when Jerry beat up a former firefighter who was gay. In Season 2, when Peter came home to help with his mother's Alzheimer's, Jerry found him having sex with his partner, forcing him to confront his homophobia. Peter returned for a cameo in Season 3 to see Jerry after he had a heart attack. Peter soon got married to his domestic partner after Jerrys heart attack, with Jerry reluctantly as the best man in the wedding. Due to the extended illness of Peter's mother, Peter got the pension and widow benefits from Jerry's death. Peter still to this day does not know the truth behind his father's death.
Firefighter James "Jimmy the Jew" Kelly (Chance Kelly) - A firefighter from another firehouse introduced in Season 4. His nickname is meant to be ironic since he is not Jewish, but rather very anti-Semitic and racist. He and Lou both try to lure firefighter basketball phenom Black Shawn to their firehouse. Lou blackmails Jimmy into backing off when he catches him having an affair with another firefighter's wife.
Lieutenant John "Stack" Stackhouse (Matt Mulhern) - A lieutenant from another firehouse introduced in season 3. Stack went to Probie school (in which he was considered a "hot-shot", and the best Probie in their class) with Tommy, Jimmy, and Needles. Stack is injured in a fire, and is very badly burned. Mike is able to get him out of the fire, but he is so badly burned, that he ends up in the hospital. He later has his legs amputated, and his wife mentions that they want to take his hands as well. Tommy visits and stays with him daily, along with Stack's wife Deb Stackhouse. Tommy tells Stack that even if he lives, his life won't be the same, and that he wouldn't want to live as a "vegetable", and that he should let go, and just give up on living. The next morning, Stack passes away.
Honorary Firefighter Paulie (David Vadim) - A mentally challenged honorary firefighter, who Tommy works with in the station he is transferred to in the first few episodes of the second season. He looks up to Tommy, and is very upset with him when he transfers back to his old firehouse. It is implied that he lives with his mother, who doesn't allow him to take the ferry.
Firefighter Patrick "Balls Out" Mahoney (Will Chase) - A former firefighter who went to the academy with Sean Garrity. Pat contracted Lung Cancer due to 9/11. When his cancer reached terminal stage, Mike and Sean took Pat around to all the people he saved out of fires over the years, and by Pats request they also took him to a ballet. After he visits the people he saved over the years now feeling regret for some of them, Pat died in Sean's car while driving down the road. A memorial service was originally held for Pat in Central park which was a restroom pavilion, much to the crew's dismay. The 62 truck crew stole the memorial plaque and put it on the first floor of City Hall.
Firefighter Mungo Monahan (Cam Neely) - A hard nosed firefighter and a member of the FDNY hockey team. Mongo is well known for playing hockey without a helmet.
Firefighter Patrick Ryan (Lyndon Byers) - Another FDNY hockey nut and co-captain of the team next to Tommy. In season 1, Ryan was trying to date Sheila. After Tommy finds this out along with his stubborn leadership skills, Tommy beats up Ryan during the Cop vs Firefighters game and has him kicked off the team. But later on by Tommys request, Ryan returns to the team.
Lieutenant Red Shea (Peter Maloney) - A retired 50 year firefighter and the Uncle of Lieutenant Ken Shea. Red served alongside Tommy's father, Michael. Red shows up in season 3 to help Lou through his rough patch. Red's health is deteriorating like Mr. Gavin's, so they both move in together and help each other. Red is last seen in the season 5 premiere at Michael Gavin's funeral laying a bottle of Irish whiskey at his coffin.
Firefighter Greg Kelly (Rob Leo Roy) - A firefighter that was having an affair with Lou's ex-wife after Sunday church mass. Instead of berating him about it, Lou talked it out with him. Greg goes over to Lou's house and tells him that Phyllis wants a divorce. Although Lou is hurt inside, he shows no feelings and asks Greg, "Need any boxes?"
Significant others, children, siblings of main characters
Alicia Green (Susan Sarandon) (Season 3) - Alicia met Franco and the guys at a bar one night and was very attracted to him. She has lots of money, and they began seeing each other regularly. Franco began bringing his daughter Keela around, letting her stay with Alicia during the day at her large Manhattan apartment. Franco accidentally slipped and told Alicia that Keela was put up for adoption but Franco stole her back illegally from the foster family. Keela longs for a mother, and Alicia feels bad for her and gets angry at Franco, not approving of his lifestyle with many women around. Franco went to Alicia's apartment one day to find them both gone, sending him into a panic. He finds out that Alicia took Keela to Walt Disney World in Florida for ten days without his permission, angering him greatly. He awaited their return so he could get his daughter back without having to deal with the law. Franco in the Season 3 finale found out through a reunion with his daughter that Alicia has decided to send Keela away to school in France. Alicia returns in Season 4, wanting to get back together with Franco, but he is engaged. Franco, however, is willing to dump his fiance Natalie. Alicia refuses to let him.
Danielle "Candy" Callahan (Milena Govich) - A hooker who has convinced Lou that she wants a new life. She is in fact a ruthless con artist who has conned a lot of money out of multiple victims, including Lou. Lou eventually discovers that Danielle was arrested for selling drugs to an undercover police officer, which helps lift him out of his depressed mental state. In Season 5, she reappears in Lou's life after getting out of jail. After Lou's vehement dismissals, he eventually lets her move in with him. Later in the season, as the two are about to be married, Lou discovers that her real name is Barbara Callahan and she is wanted in Florida. Realizing this is the only reason she wanted to marry him, Lou tells her he has called authorities to come arrest her. While continuing to deny Lou's accusations, Candy flees.
Jeannie Reilly (Peggy Scott) - Jeannie Reilly is the wife of Jerry Reilly. She suffers from Alzheimer's. It is suggested that Jeannie does not know about her husbands death due to her condition.
Rose Atwell (Kate Burton) - Jeannie Riley's home health care nurse hired by Jerry. Rose and Jerry share a connection because her late spouse also had Alzheimer's before his death. After Jeannie is privately housed, Rose continued to talk to Jerry, leading to a one night sexual relationship. After Jeannie's estranged older brother Bud catches Rose in a nightgown, Bud rips up a check that could have helped out his sister. Jerry stops seeing Rose.
Karlene Sampson (Harriett D. Foy) - An employee at the retirement home where Chief Reilly's wife lives, and an illegal alien. She befriends the Chief by having a frank discussion with him about his wife and advises him to move on. The Chief and Karlene started dating towards the end of Season 3. During intercourse with Karlene, the Chief had an apparent heart attack, and she refused to call 9-1-1 because of her illegal immigrant status. She has not appeared since, but it is implied that the Chief turned her in as payback for leaving him to suffer the heart attack.
Phyllis Shea (Siobhan Fallon) - Phyllis is Lieutenant Shea's ex-wife, who divorces him in Season 1 after the revelation that both Kenny and Phyllis were guilty of infidelity.
Theresa Gilardi a.k.a. Fat Chick (Ashlie Atkinson) - Silletti's love interest for several episodes of Season 1, making him the butt of jokes at the firehouse because she is overweight. She breaks up with Silletti, saying that she knows from past experience where the relationship will end up. Silletti then stalks her for a short time.
Nez Valenzuela (Patricia Velasquez) - Keela's mother and Franco's former love interest. Also a drug addict. Appears in season 1 to reveal to Franco that they have a daughter together. After this she starts a sexual relationship with Sean Garrity. Nez dies of an overdose in a nightclub in front of Sean after her and another woman fought.
Keela Valenzuela (Cailin Stollar) - Franco's daughter. She was taken in by Franco after her mother, Nez died from an overdose. Keela was put in a foster home for a short time, but Franco took her after Sean convinced him. In Season 2, while Franco recovered from an injury at the end of Season 1, Keela took some prescription painkillers that Franco had been taking and she was taken to the emergency room and Laura helped Franco care for her. In Season 3, after Laura left, Franco met Alicia. Franco told Alicia that he had taken her away from her foster family. Alicia then took Keela without Franco's consent, giving her a "real mother." She is given a great life with Alicia, including her own nanny. Franco finally sees Keela again briefly during the Season 3 finale, where she says that he did his best raising her and that's all that matters, which comforts Franco. Keela then leaves to attend a private school in Paris. She eventually returns to New York, but continues to stay with Alicia.
Natalie Baker (Sherri Saum) - A photographer who hit on Franco at a bar and they started going out soon after. Natalie would never invite him to her home because she had an older brother named Rich who was mentally ill. Their relationship hit a bump when Rich falsely accused Franco of insulting him. When Natalie saw a picture of Keela, she realizes that Keela looks a lot like her, and that Franco's interest in her may be connected to his missing his daughter. Their relationship becomes more serious and Franco eventually proposes to her, however she breaks it off when she realizes that he is not entirely over Alicia. To Franco's dismay, Natalie quickly finds another boyfriend and contemplates moving to Chicago with him.
Rich Baker (Cornell Womack) - Natalie’s older brother. He's mentally ill, has violent outbursts, eats anything he sets his eyes upon. He is also an idiot savant, as he is able to memorize entire textbooks with incredible ease. To impress Natalie, Franco brought Rich to the firehouse, but he wandered off. Rich then sabotaged Franco's relationship with Natalie by claiming that the firefighters insulted him. Franco realizes that Rich is just scared of losing his sister, so he asks Rich's permission to continue dating Natalie. Flattered, Rich approves. Rich eventually shows more love towards Franco than his own sister. He also wants to be on his own because he has a girlfriend, a mentally-handicapped wheelchair user named Barbara, whom he wants to marry so he can have sex with her (they marry in the Season 4 finale). Rich is left in Franco's care when Natalie visits Chicago. Rich enjoys profanity-especially calling Franco a "nigger" whenever angry at him. Franco attempts to then tell Richard that he is Puerto Rican and not black. This is a running gag throughout Richards appearances and usually involves Richard calling Franco this in front of black people and Franco having to calm these same people.
Sister Theresa Azzurro (Susan Misner) - Lou's girlfriend from the end of Season 3 to the middle of Season 4. Theresa is an ex-nun. Lou met her at a supermarket when she was in the middle of leaving the church. She has a huge sex drive due to never being with a man before, which eventually tires Lou out. He refuses to have sex with her anymore so they could have a real relationship, but this just leads her to sleep with Lou's cousin, Mike. Lou breaks up with her soon after due to this and her refusal to have children.
Mike Shea (Artie Lange) - Lou's cousin and Red's son. He operates a fishing boat on Long Island and offered Lou a position if he quit the FDNY. However, Lou suffered from heavy seasickness and could not take the job. Mike sleeps with Lou's girlfriend Theresa, but claims he was the victim due to her large sexual appetite. Although Lou forgives his cousin, he wants revenge and gets it by sleeping with Mike's girlfriend, Latrina (although he is more attracted to her cooking). When he tells his cousin, Mike reveals that he asked Latrina out for the sole purpose of having Lou cheat with her to make them even. Mike is actually more furious that she cooked for Lou behind his back.
Nell Turbody (Paige Turco) - Damien's former teacher who likes to be called Ms. Turbody. Ms. Turbody was sleeping with Damien, but Tommy found out and intervened, only to also fall to her seductions. It turned out that Ms. Turbody was sleeping with two other students at Damien's school. She was soon arrested for this, and it was revealed that she had chlamydia. The two students Ms. Turbody slept with became infected with the disease, but Tommy and Damien were not.
Roger Mills (Jay Potter) (Season 1) - Janet's boyfriend. Tommy had problems with Roger, including a fight in Janet's kitchen. He also spied on Roger and Janet using Johnny's NYPD connections. Tommy was eventually jumped by Roger's friends. Roger was arrested but Tommy dropped the charges. After that, Janet broke up with Roger.
Sean Murphy a.k.a. The Murphy Kid - Colleen's boyfriend. Tommy did not like him. The Murphy Kid and Colleen get into a car crash on their way to a Matchbox Twenty concert. Colleen broke up with him after that.
Sondra Warren - (Paula Devicq) - Billy's ex-wife who was seeing Lt Shea in Seasons 1 and 2.
Dwight Howard (Michael J. Fox) - Janet's new boyfriend in season 5. He uses a wheelchair because of a car crash. He does not get along with Tommy, and heavily antagonized him during their first meeting. He later makes amends with Tommy, who starts getting uncomfortable around Dwight given that Dwight is a fast driver and he drinks heavily when behind the wheel. Fox won the Emmy for Guest Actor in a Drama Series for this role.
Nona Espisito (Jennifer Esposito) -- A woman that Tommy dated who rescued him from a fire. She is a volunteer firefighter who emasculated Tommy by single handedly carrying him from the burning house. Once after her and Tommy had sex, she broke it off with him.
Troy Vollie (Desmond Harrington) - Sheila's boyfriend in season 4. He rescued her from the fire she accidentally started in her new home. He is obsessed with Tommy, and considers him his hero. He buys and wears exactly the same clothes Tommy has, has a shrine dedicated to him, and even goes as far as to scream at Izzy, after he pulled Tommy out of a hockey game against the NYPD. Tommy however, doesn't feel at all the same way, and finds him strange and irritating. He breaks up with Sheila after seven children die in a fire that 62 Truck responded to, no longer considering Tommy a hero.
Kelly Mcphee (Maura Tierney) - A woman who rushes into a fire that the crew is fighting, retrieving a mysterious metal suitcase. Tommy shows both a romantic interest in Kelly (much to the chagrin of Janet and Sheila) and a strong curiosity over the contents of her suitcase. In season 7 she returns and it is revealed she has developed breast cancer. After she was diagnosed as cancer free, she embraces Tommy. But later rebuffs him and asks him to leave.
Father Phil Gallagher (Peter Gallagher) - A priest who becomes a recurring character in season 6. A fire occurs in Phil's church leading Tommy and the crew to save a Virgin Mary statue in there. After this incident Tommy visits Father Phil frequently to discuss his worries about family and the afterlife. While Phil is a priest, he expresses sexual attraction to Janet and flirts with Sheila, who seems to be a little interested as well.
Terrence Garrity (Kevin Chapman) - Sean Garrity's older and much more dim-witted brother. Terrence is viewed as a "mamas boy" as he still lives with Ms. Garrity. Terrence and Sean have a sibling rivalry with each other due to them bickering most of the time with each other.
Leslie Garrity - (Kathleen Chalfant) Sean and Terrance Garrity's mother. Her and Terrence stay at Seans apartment for a short time when Sean goes into surgery for kidney cancer. She reveals that she loves Terrence a little more than Sean due to Terrence being older, and being more slow-witted than Sean.
Debbie (Brette Taylor) - Sheila's rebound girlfriend after Tommy and Sheila broke up in season 2. Even after getting with Debbie, Sheila still has feelings for Tommy, sending Debbie into jealous, violent rages. After Debbie lays hands on Sheila for the last time, Tommy comes over to intervene. Tommy persuades Debbie to hit him in the face three times, giving Tommy an emotional breakdown over losing his son, Connor. Soon after this, Sheila leaves Debbie.
Asshole - Tommy's dog in Season 1. He chews up hockey jerseys and constantly pesters Tommy. Tommy eventually grows to like the dog; in episode 1-11, Uncle Teddy reveals that he accidentally let it go and it was killed by a car. Tommy, distraught, walks into his backyard, picks up one of the dog's bones, and begins to weep over the loss of both his mother and dog.
Charlie - Tommy's dog introduced in Season 4. He is first encountered outside of Tommy's new apartment, where he "chases" Tommy. Charlie is present during the "Gavin family AA meetings". Tommy takes him to a park, and tries to teach him how to fetch, but he is unsuccessful. When Tommy secretly spends his nights in the firehouse, Charlie spends them with him.
Todd CollinsTodd Carroll - Collins is a member of the NYPD who often argues, fights, and plays hockey with Tommy. In Season 3, Tommy went into the locker room after he started crying during a hockey game. Collins saw this and was surprisingly sympathetic. It turns out that he too suffered from random bouts of crying after his partner was killed (survivor's guilt). He advises Tommy to drink heavily, since that is the only thing that stops it. In season 7, Collins (now a detective) reluctanly helps Tommy with information that gets Tommy's suspension lifted.
Luis Perez (Manny Perez) - An NYPD detective and John Gavin's former colleague. Luis is openly a homosexual. Was with Johnny on the stakeout that Johnny was shot at. After this, he helps out Tommy with getting a face to face with Johnny's killer, and finding Colleen in season 4. Luis eventually transfers to Seattle, Washington.
Jesus Christ (Bernardo De Paula) - Jesus Christ, along with Mary Magdalene, is a part of Tommy's recurring visions in Season 2 with Jesus constantly trying to guide Tommy to do the right thing and Mary putting a more realistic and workable spin on Jesus' guidance.
Larry Bird (Birdy) (Chris Bowers) - Owner of Birdy's, an Irish pub with a heavy Celtics theme. To meet his wife's health care bills, Chief Reilly takes a second job there during Season 3, on the assumption that he will be tending bar, but Birdy allows Jerry to work only as a bar-back. Further, Birdy does not pay Jerry his wages. When Tommy and Franco learn of the abuse, they confront Birdy, who promptly fires the Chief. In response, Tommy arranges for Birdy's car to be suspended by a construction crane. After this, Birdy pays Jerry what he owed him.
Donna (Kristina Klebe) - Mickey's girlfriend, who is most likely to be one of the reasons he left the church.
Derek (Anthony Perullo) - An alcoholic, who becomes sponsored by a reluctant Tommy after Tommy gets his 12-month chip from AA. Becoming an annoyance with frequent phone calls whenever he feels the urge to drink, Derek eventually gets a job at the fire crew's bar.
Snezyana "Mrs. Needles" Nelson (Madison McKinley) - Chief Nelson's mail-order bride from Russia. Dubbed "Mrs. Needles" by the crew. In her first appearance, Damien had informed the crew that he had seen her getting out of the car and noticed she didn't have any panties on under her skirt. Thus, the crew went out of their way to see for themselves. Seen in only a few episodes, no one truly knows about the full extent of Snezyana and her relationship with her "husband" Needles. In the season 5 episode "Lesbos", a severely drunk Snezyana makes out with two lesbians and gives oral sex to Derek. She was also about to give oral to Black Shawn had Needles not intruded, which hints that she may have no love for Needles at all. But despite all of this Needles shows that he cares for Snezyana very much and takes her back to his office to clean her up. Needles later divorces her for personal reasons, one is implied Tommy knew she was an illegal immigrant and was holding it over Needles' head after he would continue to hold Tommy's in-house misfortunes over his head.
Pam Keppler - A news reporter in season 7. Pam did the story on Jimmy Keefe's memorial. But when she got too close into the story asking Tommy cheap shot questions, Tommy cursed her out on camera, causing his suspension. After this, Pam digs deeper on the members of 62 truck. But Tommy and Needles finds out that Keppler had been arrested for DUI and blackmailed the arresting officer by giving him fellatio, which was caught on film. In return, Sheila takes the oral sex film and blackmails Keppler into dropping the rest of the story about Jimmy, Tommy, and the rest of 62 truck.