Gerald Peter Reilly, of Irish descent, was a 23-year veteran of the FDNY. Jerry served as a Battalion Chief of the 15th Battalion in northern Harlem, Manhattan. Jerry lived in Queens, New York his whole life.
At the beginning of the series, Jerry assaults a gay firefighter only to reveal later that he has a gay son who works for the Boston Fire Department that he has all but disowned. He finally comes to grips with his son's homosexuality, if only so he could find someone to help him take care of his wife who is now suffering from Alzheimer's. At the end of season two, he is forced to put his wife in a home when her mental condition becomes too much for him to handle. Their separation is very painful for the Chief emotionally as well as financially, as the cost of his wife's care has used up whatever money he had saved.
Jerry is forced to get another job at a bar to help pay the bills but is forced to quit said job due to tension with his boss. He also starts a relationship with a woman named Rose, which was discovered by Jerry's brother-in-law, who was ironically just about to loan him $5,000 because Jerry had been so faithful to his wife despite her illness. This incident leads to Jerry breaking up with Rose, but on the positive side, Jerry gambles on a horse race and wins a lot of money. Since the horse was not the favorite to win and not even the crew's original pick (Mike was tasked with the gambling money, but bet on the wrong horse at the OTB), Jerry wins enough money to easily support his wife. He soon afterwards starts a relationship with his wife's nurse, an illegal immigrant named Karlene, who urged him to move on and not be burdened by his wife's state, since she has forgotten him. Near the end of the third season, Jerry suffers a heart attack while having sex with Karlene, who then leaves him without calling 911 so she won't be discovered at his house. The next day Franco, Sean, Mike and another chief find Jerry face down on the ground and take him to the hospital. He survives and is recovering.
Jerry is seen exercising and has lost a lot of weight. He is preparing to take a physical test to return to work as a firefighter. His son, Peter, asks him to be bestman at his commitment ceremony. Jerry reluctantly agrees and attends. He later takes the test and is informed that the damage to his heart is too much and is not allowed to return to active duty. He is offered a desk job in the FDNY headquarters.
In the episode "Commitment," Jerry takes his own life with a handgun after attending his son's commitment ceremony with his new husband, Steve, and helping Tommy Gavin avoid his potential arson investigation with the FDNY. The crew had given him a set of golf clubs, in which Jerry is seen playing with prior to his suicide. After his suicide, his death certificate rules his death as congestive heart failure in order for his pension and life insurance to be collected by his heirs - namely his son Peter, due to Jerry's wife being privately housed with Alzheimer's.
Unlike the other dead characters, Jerry is never seen as a ghost during the rest of the series.
- "Gay". Rescue Me.
- "Kansas". Rescue Me.
- "Hell". Rescue Me.
- "Baby Face". Rescue Me.