William Dieterle filled in as director when William Keighley got the flu. Similarly, cinematographer George Barnes took over as director of photography when Sol Polito fell ill.
Freddie Bartholomew was originally considered for the central dual role. Instead, real-life twins Billy Mauch and Robert J. Mauch were hired.
MGM bought the rights to Mark Twain's novel in 1935 for $100,000, but never filmed the story. Eventually, Warner Bros. secured the rights.
The coronation scene was on a set that duplicated Westminster Abbey and took seven days to shoot.