Mel Brooks cannot read music. "Springtime for Hitler" and "Prisoners of Love" (as were all the songs Brooks writes for his films) were hummed into a tape recorder and transcribed by an expert. When Brooks adapted the movie into a stage musical, he wrote the entire score by himself using the same method.
Gene Wilder said in an interview on TCM that at the first reading of the script, he excused himself to leave for a dentist appointment he could not miss, when in fact he had to go to the unemployment office to collect a check for $55 he desperately needed at the time.
Mel Brooks has said that one of his "lifelong jobs" is "to make the world laugh at Adolf Hitler." The film was a way to enact vengeance through comedy. "The only real way I could get even with Hitler and company was to bring them down with laughter," Brooks said.
Mel Brooks says that producer Joseph E. Levine wanted to fire Gene Wilder after seeing some of the footage because he thought he "stunk." He wanted to give Mel Brooks $35,000 more to find someone better, but Brooks convinced Levine that Wilder was fine, and would make the movie work. Wilder would be nominated for an Academy Award for his performance.
Roger Ebert recounted how he was in an elevator with Mel Brooks and Anne Bancroft in New York City after the film premiered. A woman got onto the elevator, recognized him and said, "I have to tell you, Mr. Brooks, that your movie is vulgar." Brooks replied, "Lady," he said, "it rose below vulgarity."