Jerry Adler, younger brother of Larry Adler, taught James Stewart how to hold the harmonica and mime its playing for the movie, and was the person who performed the music supposedly done by Stewart, who continued playing the instrument after the movie wrapped.
At Ma McCorkle's (Mary Gordon's) house, Police Lieutenant Grady (James Burke) is told about the tomato-throwing incident that had taken place earlier that day. When he says, "It must've been good", someone responds, "Good? It was perfect!", to everyone's amusement. This is in reference to a running joke in Paulette Goddard's earlier film, Second Chorus (1940), where the gag "Vas good?" "Vas per-fect" (in a Russian accent) is exchanged in a couple of scenes.
James Stewart shot this film simultaneously with Ziegfeld Girl (1941) at MGM, and shuttled between studios as required.
The only full-length feature produced by James Roosevelt, eldest son of FDR, although he was Executive Producer on seven shorts the same year. His short career in Hollywood was in part to protect his father from accusations of nepotism following James's previous Hollywood appointments.
James Stewart once said that he caught this movie by accident on television and watched the scene where he is squirted with a seltzer bottle. Initially he thought he had tuned in to a sitcom, until he realized it was one of his own movies.