Bryan Cranston Dalton Trumbo
Audrey Hepburn Princess Ann (archive footage) (uncredited)
Elle Fanning Niki Trumbo
Diane Lane Cleo Trumbo
Lucille Ball Self (archive footage) (voice) (uncredited)
Helen Mirren Hedda Hopper
Eddie Albert Irving Radovich in Roman Holiday (archive footage) (uncredited)
John Goodman Frank King
Jean Simmons Varinia (archive footage) (uncredited)
Stephen Root Hymie King
Deborah Kerr Self (archive footage) (uncredited)
Alan Tudyk Ian McLellan Hunter
Robert Taylor Self (archive footage) (uncredited)
Danny Kaye Self (archive footage) (uncredited)
James Garner Self (archive footage) (uncredited)
Michael Stuhlbarg Edward G. Robinson
Laurence Olivier Crassus (archive footage) (uncredited)
Gregory Peck Joe Bradley (archive footage) (uncredited)
Cary Grant Self (archive footage) (uncredited)
Adewale Akinnuoye-Agbaje Virgil Brooks
John Getz Sam Wood
Madison Wolfe Niki Trumbo (age 8-11)
Ronald Reagan Self (archive footage) (uncredited)
Johnny Sneed Robert Stripling
Lauren Bacall Self (archive footage) (uncredited)
Richard Portnow Louis B. Mayer
Janice Williams Producer
Dalton Trumbo Himself (archive footage)
Louis C.K. Arlen Hird
Sean Bridgers Jeff Krandall
David James Elliott John Wayne
Mark Harelik Ed Muhl, Edward 'Ed' Muhl
Jay Roach Director, Producer
Roger Bart Buddy Ross
John McNamara Screenplay, Producer
Peter MacKenzie Robert Kenny
Dan Bakkedahl Roy Brewer
Mattie Liptak Chris Trumbo (Age 13-17)
Jeri Habberstad Stunt Double
Dean O'Gorman Kirk Douglas
Christian Berkel Otto Preminger
Rio Hackford Reporter
James DuMont J. Parnell Thomas
Theodore Shapiro Original Music Composer
Kevin Kelly Brown Producer
Dane Rhodes Reporter
Gary Archer Prosthetics
Toby Nichols Chris Trumbo (age 6-10) (as Tobias McDowell Nichols)
Meghan Wolfe Mitzi Trumbo (age 6-8)
Rhonda Laizer Trumbo Friend (uncredited)
Geoffrey Haley "A" Camera Operator, Steadicam Operator
Michael London Producer
David Rubin Casting
George Parra First Assistant Director
Lisa Marinaccio Art Direction
John Neisler Jury Foreman
Cindy Carr Set Decoration
Garrett Hines Andrew Hird
Jesse Rosenthal Art Direction
Alan Baumgarten Editor
Laura Flannery Party Goer
Jaclyn Bethany Starlet (uncredited)
Daniel Orlandi Costume Designer
Heather Arthur Stunt Coordinator
Mark Ricker Production Design
Monica Levinson Producer, Unit Production Manager
Jim Denault Director of Photography
Scott August Second Assistant Director
Veronica Parks Showgirl (uncredited)
Laurie Lieser Associate Producer
Shivani Rawat Producer
Kelly Mullen Executive Producer