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