Humphrey Bogart was originally chosen to play Harold Goff. However, Ida Lupino had just finished shooting They Drive by Night (1940) and High Sierra (1941) with Bogart, and they had not gotten along. Lupino protested, and because she was a bigger name than Bogart at the time, she got her way. An angry Bogart shot off a telegram to Jack L. Warner asking, "When did Ida Lupino start casting films at your studio?"
After the courtroom scene, when Jonah and Olaf stop in front of a music hall to exchange a couple of words, the music coming out of the hall is "The Merry-Go-Round Broke Down", better known as the theme from the Looney Tunes cartoons, another Warner Brothers property.
This film and The Maltese Falcon (1941), which was released the same year, helped set the tone for even darker and more cynical noirs that would follow, like Double Indemnity (1944) and The Postman Always Rings Twice (1946).
Leo Gorcey repeatedly blew a simple line of dialog. Fed up, director Anatole Litvak stormed over to him and shouted, "Gorcey, as an actor, you stink!" Gorcey yelled back, "Don't you ever, ever scream at me like that again!" and stormed off the set. He returned later to shoot the scene and blew the line again. This time, Litvak walked over to him calmly and whispered in his ear, "Gorcey, as an actor, you still stink. And notice that, this time, I'm not shouting."
Goff orders two Zombie cocktails at the club bar. First credited to restaurateur Don the Beachcomber in 1934, the potent tropical libation was part of the Latin and tropical influence of the era, in entertainment, fashions, travel, and more.