|This article does not cite any references or sources. (November 2011)|
|Created by||Carter Bays
|Portrayed by||Jason Segel|
|Nickname(s)||Marshmallow, Big Fudge, Vanilla Thunder, Beercules, The Kid, Sports Guy, The Human Turnstyle|
|Family||Marvin Eriksen, Sr. (father, deceased)
Judy Eriksen née Gunderson (mother)
Marvin Eriksen, Jr. (son)
Marcus Eriksen (brother)
Martin Eriksen (brother)
|Spouse(s)||Lily Aldrin (2007-present)|
|Children||Marvin Waitforit Eriksen III|
|Relatives||Olaf (grandfather, deceased)
Marcus Eriksen Jr (nephew)
Mickey Aldrin (father-in-law)
Janice Aldrin (mother-in-law)
Rita Aldrin (grandmother-in-law)
Morris Aldrin (grandfather-in-law)
Character profile 
Marshall is an easy-going, naive optimist from St. Cloud, Minnesota. At the start of the series, Marshall lives with his best friend Ted Mosby and his long-time girlfriend, Lily Aldrin; he proposes to her in the pilot episode. Marshall is an avid Minnesota Vikings fan.
Born in 1978 and of Scandinavian descent, Marshall met Ted and Lily during their freshman year at Wesleyan University. He attended and later graduated Columbia Law School. Even though he stands at 6 ft 4 in (1.93 m), he is the shortest male member of his family. Marshall became a lawyer because he was interested in environmental protection laws. Ultimately, he accepted a job at a corporate law firm where his only client is an amusement park riddled with various safety violations. He later joins the legal team at Goliath National Bank, where Barney Stinson also works. Later, in season 6, he quits his job at Goliath National Bank to work at an environmental law firm. In season 8, after winning a large court case, but receiving a small amount of money in damages, Marshall is convinced by Brad, his former classmate, friend, and prior rival in a case, to become a judge. Marshall is seen in front of the judiciary committee in the episode, "Twelve Horny Women".
He and Lily have a relationship, but it has been tested at various times throughout the series. In "Come On", Lily, who has been having cold feet about their approaching wedding, announces that she has been accepted to an art fellowship in San Francisco and leaves to find out who she is outside of a relationship. Marshall is devastated and spends the next few months in a deep depression. When Lily returns to New York and asks him to take her back, he refuses. They eventually reconcile and resume their engagement in "Swarley", and get married, albeit with some complications, in "Something Borrowed".
Marshall is fascinated with the paranormal, specifically Sasquatch and the Loch Ness Monster, both of which he believes are real. He is also fascinated in the existence of aliens. He can play the piano fairly well, as seen in the episode "Slapsgiving". It is revealed in "Last Cigarette Ever" that in the future, he and Lily have a son. In early 2011, after being told Marshall and Lily are capable of having a baby, Lily tells Marshall that his father had a fatal heart attack; his father's death causes him to change perspective on his life, which leads to him quitting his job at GNB and pursuing a career in environmental law, as well as attempting to start a family with Lily.
In the season six finale, Marshall is given a job interview with a local law firm, but runs out on the interview because Lily supposedly has food poisoning and he believes he too will get sick. The next morning, Lily reveals to him that she was sick only because she is pregnant. In the "The Naked Truth", Marshall is given a job offer from Garrison Cootes. Later, in the Mystery vs. History, while decorating the nursery for their new baby, he and Lily are tempted by Barney and Robin to find out the sex. They do, in the end, find out that they are having a boy. With the baby's impending birth, Marshall conditions himself for various parenthood situations by using a watermelon as a practice baby. Lily asks Barney to trick Marshall into taking a vacation in Atlantic City so he could unwind. At a casino, Barney proposes wearing the Ducky Tie again if they can turn off their phones for one hour and drink 100 tequila shots. One hour later, Barney turns his phone back on to find Lily's voice-mails to inform that she had gone into labor. Marshall eventually gets to the hospital in time for his son's birth and decides to name him, Marvin Wait-for-it Eriksen, in memory of his father and the middle name as a promise to Barney.
- The spelling of Marshall's last name is inconsistent. On his Facebook page it can be seen as Erickson, but when he visits his family home in Minnesota it is shown as Eriksen.
- Marshall possesses a prodigious talent for any kind of strategy game. In "Atlantic City," while watching Barney play a bizarrely obscure table game, Marshall grasps the rules of the game so quickly that he is able to coach Barney to win the game and all of the money on the table, despite the fact that the game is conducted entirely in Mandarin Chinese. In "Game Night," the gang excludes Marshall from competing in their board game sessions, since he invariably wins every game in which he is a player. Marshall is also seen to be the reigning skeeball champion at a local college bar in "Jenkins."