- Executive Meddling: Louis B. Mayer strongly opposed the casting of both William Powell and Myrna Loy, considering the former too old and the latter too typecast as "exotic" femme fatales. W.S. Van Dyke, who had already directed the duo in Manhattan Melodrama, insisted on casting both of them and Mayer eventually relented.
- Never Work with Children or Animals: Mostly averted; Skippy, the dog playing Asta, was an exceedingly well-trained animal and the only trouble occurred when he became overexcited and bit Myrna Loy on the hand during one scene. On the other hand, his trainer prevented Skippy from interacting with Powell and Loy between takes so that their interactions would seem more spontaneous.
- Playing Against Type: This was one of the films that helped Myrna Loy finally break out of the "villainous foreign vamp" ghetto she had been toiling in. Ironically, she went on to become best known for playing nurturing wives and mothers.
- Throw It In!: During a break in filming, William Powell started shooting down Christmas ornaments on the set with an air gun. Van Dyke loved it and decided to add a scene where Nick did the same thing.
- Write Who You Know: It's generally assumed that Hammett based Nick and Nora and their relationship on himself and his partner, writer Lillian Hellman (he was also a retired detective).
Trivia / The Thin Man