Paul Giamatti as Paul Hunham

Dominic Sessa as Angus Tully

Da'Vine Joy Randolph as Mary Lamb

Carrie Preston as Miss Lydia Crane

Brady Hepner as Teddy Kountze

Ian Dolley as Alex Ollerman

Jim Kaplan as Ye-Joon Park

Michael Provost as Jason Smith

Andrew Garman as Dr. Hardy Woodrup

Naheem Garcia as Danny

Stephen Thorne as Thomas Tully

Gillian Vigman as Judy Clotfelter

Tate Donovan as Stanley Clotfelter

Darby Lee-Stack as Elise

Bill Mootos as Mr. Endicott

Dustin Tucker as Mr. Rosensweig

Juanita Pearl as Mary's Sister Peggy

Alexander Cook as Priest / Bartender

Liz Bishop as Office Lady

Cole Tristan Murphy as Toothbrushing Student

Will Sussbauer as Cobb Salad Student

Carter Shimp as Weed Buyer Harriman

Michael Malvesti as Christmas Tree Guy

Dakota Lustick as Christmas Tree Helper

Melissa McMeekin as Hooker

Jonathan von Mering as ER Doctor

Rena Maliszewski as ER Nurse

Osmani Rodriguez as Pharmacist

Oscar Wahlberg as Pinball Player

Dan Aid as Vietnam Vet Kenneth

Mike Kaz as Hip Party Guest

Kelly AuCoin as Hugh Cavanaugh

Colleen Clinton as Mrs. Cavanaugh

Fred Robbins as Santa Claus

David J. Curtis as Psychiatric Orderly

Pamela Jayne Morgan as Waitress

Davis Robinson as Maître d'hôtel

Joe Howell as Liquor Store Cashier

Peter Krasinski as Choir Leader

Greg Chopoorian as Jason Smith's Father

Ian Lyons as Miss Crane's Boyfriend

Kevin Fennessy as Irritated Movie Patron

Kevin Daigneault as Barton Parent (uncredited)

Bhanu Gopal as Boston Streeter / Pedestrian (uncredited)

Quinn Stone as Student