Joseph Gordon-Levitt as Ethan

Seth Rogen as Isaac

Anthony Mackie as Chris

Lizzy Caplan as Diana

Jillian Bell as Betsy

Mindy Kaling as Sarah

Michael Shannon as Mr. Green

Lorraine Toussaint as Mrs. Roberts

Randall Park as Boss

Ilana Glazer as Rebecca Grinch

Nathan Fielder as Joshua

Heléne Yorke as Cindy

Aaron Hill as Tommy Owens

Tracy Morgan as Narrator / Santa

Darrie Lawrence as Nana

James Franco as Self

Miley Cyrus as Self

Kamal Angelo Bolden as Kamal

Baron Davis as Self

Chuck Muckle as Piano Playing Uncle

Curt Bouril as Cindy's Husband

Brooke Liddell as Cindy's Daugher

Kiley Liddell as Cindy's Daughter

Jason Mantzoukas as Bad Santa #1

Jason Jones as Bad Santa #2

Clem Cheung as Deli Owner

Harolyn Blackwell as Opera Singer

Natalie Knepp as Coat Check Girl

Cameron Earl Thrift as Singing Kid

Jeremy Vimes as Hunan Waiter

Gabriel Long as Karaoke Singer #1

Michaela Sprague as Isaac's Daughter

Euan Morton as Coat Check Patron

Marilyn O'Connell as Old Lady

Richard Hughes as Train Conductor

Theodora Miranne as Woman

Nicola Fiore as Exotic Dancer (uncredited)

Aly Mang as Party Attendee & Pro Athlete Girlfriend (uncredited)

Marija Skangale as Snow Globe Dancer (uncredited)

Bill Walters as Christmas Bartender (uncredited)

Hannah Townsend as Tommy's Hot Girl (uncredited)

Oliver Solomon as Karaoke Singer #1 (uncredited)