Bryan Cranston
Dalton Trumbo
Helen Mirren
Hedda Hopper
Elle Fanning
Nikola Trumbo
Michael Stuhlbarg
Edward G. Robinson
David James Elliott
John Wayne
Alan Tudyk
Ian McLellan Hunter
James DuMont
J. Parnell Thomas
Richard Portnow
Louis B. Mayer
Adewale Akinnuoye-Agbaje
Virgil Brooks
Mattie Liptak
Chris Trumbo (Age 13-17)
Dean O'Gorman
Kirk Douglas
Garrett Hines
Andrew Hird
Christian Berkel
Otto Preminger
Toby Nichols
Chris Trumbo (age 6-10) (as Tobias McDowell Nichols)
Dalton Trumbo
Himself (archive footage)
Laura Flannery
Party Goer
Madison Wolfe
Niki Trumbo (age 8-11)
Johnny Sneed
Robert Stripling
Peter MacKenzie
Robert Kenny
John Neisler
Jury Foreman
Sean Bridgers
Jeff Krandall
Meghan Wolfe
Mitzi Trumbo (age 6-8)
Becca Nicole Preston
Mitzi Trumbo (age 9-12)
Mark Harelik
Edward 'Ed' Muhl
Jaclyn Bethany
Starlet (uncredited)
Kate Kuen
Ethel (uncredited)
Suzanne LaChasse
Showgirl (uncredited)
Rhonda Laizer
Trumbo Friend (uncredited)
Jesse Lasky Jr.
Self (archive footage) (uncredited)
Joseph McCarthy
Self (archive footage) (uncredited)
Richard Nixon
Self (archive footage) (uncredited)
Veronica Parks
Showgirl (uncredited)
Ronald Reagan
Self (archive footage) (uncredited)
Julius Rosenberg
Self (archive footage) (uncredited)
Ethel Rosenberg
Self (archive footage) (uncredited)
Anne Speed
Juror (uncredited)
Joseph Stalin
Self (archive footage) (uncredited)
Eddie Albert
Irving Radovich in Roman Holiday (archive footage) (uncredited)
Lauren Bacall
Self (archive footage) (uncredited)
Lucille Ball
Self (voice) (archive footage) (uncredited)
James Garner
Self (archive footage) (uncredited)
Danny Kaye
Self (archive footage) (uncredited)
Laurence Olivier
Crassus (archive footage) (uncredited)
Jean Simmons
Varinia (archive footage) (uncredited)
Robert Taylor
Self (archive footage) (uncredited)