Main •
Jason Segel as Jimmy Laird, a therapist who works at the Cognitive Behavioral Therapy Center and is grieving the death of his wife •
Jessica Williams as Gaby Evans, a fellow therapist working with Jimmy at the Cognitive Behavioral Therapy Center •
Luke Tennie as Sean Mitchell, a patient suffering from anger management issues who has sessions with Jimmy •
Michael Urie as Brian Lorenzo, Jimmy's best friend who is a lawyer •
Lukita Maxwell as Alice Laird, Jimmy's teenaged daughter with whom he has a strained relationship •
Christa Miller as Liz Bishop, Jimmy's next-door neighbor who also helps with looking after Alice •
Harrison Ford as Dr. Paul Rhoades, a senior therapist and colleague of Jimmy's at the Cognitive Behavioral Therapy Center who has
Parkinson's disease •
Ted McGinley as Derek Bishop (season 2–present; the drunk driver responsible for Tia's fatal car accident, who ultimately befriends Jimmy and Alice • Courtney Taylor as Courtney (season 2), Gaby's sister • Amy Rosoff as Dr. Sykes (season 2, guest season 3), Paul's new doctor •
Vernee Watson as Phyllis (season 2–present), Gaby's mother
Guest •
Asif Ali as Alan (season 1), one of Jimmy's patients •
Miriam Flynn as Pam (season 1; season 3), Jimmy and Liz's heavily disliked neighbor •
Brian Howe as Kip (season 1; season 3), Brian's father •
Kelly Bishop as Susan (season 2), Paul's ex-wife and Meg's mother •
Meredith Hagner as Sarah (season 2–present), Louis' former fiancée • Tanner Zagarino as Dylan (season 2), Alice's classmate with whom she goes on a casual date •
Nora Kirkpatrick as Kellie (season 2–present), a nanny hired by Brian and Charlie • Matt Mitchell as Will Bishop (season 2-present), Liz and Derek's mature and responsible son •
Michael J. Fox as Gerry (season 3), a Parkinson's patient Paul meets at the doctor's office •
Isabella Gomez as Marisol (season 3), Sean's ex-girlfriend who comes back into his life •
Samuel Page as Casey (season 3), Sarah's new boyfriend •
Jeff Daniels as Randy Laird (season 3), Jimmy's father •
Lisa Gilroy as Kimmy (season 3), a nurse Liz sets Jimmy up with •
Candice Bergen as Constance (season 3), Derek's mother •
Matt Jones as Nick (season 3), Sofi's ex-husband •
Meg DeLacy as Peyton (season 3), Will Bishop's pregnant girlfriend ==Episodes==