He was the preeminent screenwriter of his day when Dalton Trumbo and another nine others in the Hollywood film community were summoned before Congress to testify before the House UnAmerican Activies Committee. The ten were questioned about who in Hollywood was affiliated with the Communist Party in America.
Trumbo and the others refused to testify. As became known of these and others who followed during this period, they “refused to name names.” For this act of protest against what in later years became known as a “Witch Hunt” similar to what took place in Salem in days of old, Trumbo and others became blacklisted by Hollywood. They could not get work writing, producing, directing — no one in the studio system would touch them.
Trumbo not only succeeded as a highly-paid screenwriter, he’d written and published an award-winning novel about the first world war largely seen over subsequent decades as one of the most influential ant-war novels in modern American Literature. Johnny Got His Gun
Prior to the Blacklist, Trumbo collaborated on the films Kitty Foyle and Thirty Seconds Over Tokyo. Many years after the fact, he was given sole credit for writing the Audrey Hepburn hit Roman Holiday.