Following two abortive attempts to get a project off the ground, he wrote the screenplay for ''Citizen Kane'' with Herman J. Mankiewicz. Principal photography took place in 1940, the same year that its innovative trailer was shown, and the film was released in 1941.

Upon its release, Hearst prohibited any mention of the film in his newspapers. Although it was a critical success, Citizen Kane failed to recoup its costs at the box office.