- Bryan Cranston Dalton Trumbo
- Diane Lane Cleo Trumbo
- Helen Mirren Hedda Hopper
- Louis C.K. Arlen Hird
- Elle Fanning Niki Trumbo
- John Goodman Frank King
- Michael Stuhlbarg Edward G. Robinson
- Adewale Akinnuoye-Agbaje Virgil Brooks
- John Getz Sam Wood
- James DuMont J. Parnell Thomas
- Alan Tudyk Ian McLellan Hunter
- Richard Portnow Louis B. Mayer
- Roger Bart Buddy Ross
- Dane Rhodes Reportero
- Stephen Root Hymie King
- Dean O'Gorman Kirk Douglas
- Christian Berkel Otto Preminger
- Sean Bridgers Jeff Krandall
- Madison Wolfe Nikola 'Niki' Trumbo (8-11 años)
