Mitch LarsenPlayed by Michelle Forbes
Mitch Larsen is Stan Larsen's wife, a girl from the wrong side of the tracks who found peace as a housewife and the mother of three children, Rosie, Denny, and Tom. Mitch raised Rosie to be more modest and accomplished than other girls her age, though after Rosie's death, both Stan and Mitch's sister, Terry Marek, wonder if Mitch's strict approach drove Rosie to live a secret life that led to her murder. Unbeknownst to most people, Rosie’s biological father is a man named David, whom Mitch met during a break in her relationship with Stan.
Rosie's death stuns Mitch into a grief so deep that one night she tries to recreate the experience of drowning, submerging herself in bath water for a long moment before bursting to the surface, gasping for air. Mitch spends hours in Rosie's room, staring at its contents. At one point convinced that Rosie's teacher, Bennet Ahmed, killed her daughter, Mitch influences Stan to administer justice himself. Stan drives Bennet to a secluded location and beats him so severely that he nearly dies. With Mitch overwhelmed by sadness, Terry takes charge of Denny and Tom. The one day that Mitch offers to help with the kids, Mitch becomes distracted and leaves them in the family's SUV in the garage with the motor running.
While Stan is in jail for the assault, Mitch learns that he has reconnected with Janek Kovarsky, a Polish mobster for whom Stan once provided muscle. Stan admits to Mitch that he went to Janek for a loan, but she cuts him off before he can reveal that the money was to help cover the mortgage on a house he'd recently bought to surprise her. Enraged, Mitch refuses to post Stan's bail. When he returns home after Terry posts his bail instead, Mitch tells him that the boys don't need her anymore. Stan replies that both he and the boys need her, but Mitch just sobs, "Everything about this place hurts me." That evening, she leaves her family.
While away from home, she checks into a motel and kisses a man that she meets at a bar. She also takes a teenage girl under her wing, but the girl ends up robbing her. Mitch finally returns home and, in a sign that she’s ready to move on from Rosie’s death, agrees with Stan’s suggestion to move to a new home.