Bryan Cranston revealed in a radio interview that Kirk Douglas approved of this movie, but his major complaint was that he wasn't asked to play himself.
Edward G. Robinson testified four times in front of the House Un-American Activities Committee, and the fourth time, on April 30, 1952, named Albert Maltz, Dalton Trumbo, John Howard Lawson, Frank Tuttle, Edward Dmytryk, and Sidney Buchman. He also expressed regret at his association with the Communist Party, proclaiming himself a "dupe". However, one character mentioned in the movie, Arlen Hird, played by Louis C.K., never actually existed. He is, in fact, an amalgam of several historical blacklisted writers.
Steve Martin wrote that early in his career that his girlfriend and her "different" family introduced him to new ideas and intellectual opportunities. Her father was Dalton Trumbo. Martin had never heard of Trumbo.
Director Jay Roach claimed that many of the scenes featuring Trumbo writing alone at his desk or in the bathtub were improvised by Bryan Cranston while the cameras rolled, and that Cranston was genuinely composing complete sentences on the page.
Dean O'Gorman wrote to Kirk Douglas for his advice about playing him in this movie. Douglas wrote back, telling the 38-year-old actor to be professional and trust his instinct: "Playing Kirk Douglas, forget him. Just play the part and you will be fine."