Director Frank Capra didn't want anyone to play John Doe except Gary Cooper, who agreed to the part without reading a script for two reasons: he had enjoyed working with Capra on È arrivata la felicità (1936), and he wanted to work with Barbara Stanwyck.
Director Frank Capra filmed four different endings but deemed them unsatisfactory during previews. A letter from an audience member, signed "John Doe," suggested a fifth ending that Capra liked and used in the finished film.
Contrary to popular belief, no longer version of the film exists; it has always run 123 minutes. A publicity error mistakenly listed it as 132 minutes due to a printer's typo. For years, historians assumed 9 minutes had been cut from reissue prints until the discovery of an original fine-grain master confirmed the correct runtime of 123 minutes.
Regis Toomey, who portrays Bert Hansen, had already memorized his monologue about the John Doe Clubs for his audition. On the day of filming, Frank Capra asked him if he needed to rehearse. Toomey didn't, and they shot the scene in one take.
Throughout production, director Frank Capra worried that pro-fascist American magnates such as William Randolph Hearst and Joseph P. Kennedy might pressure Warner Bros. to renege on their distribution agreement. Joseph P. Kennedy previously attempted to suppress the release of Capra's Mr. Smith va a Washington (1939) and, at the same time that Capra filmed "Meet John Doe," William Randolph Hearst attempted to suppress the distribution of Orson Welles's film Quarto potere (1941) due to its unflattering portrayal of his life.