For some unknown reason, Jack "Machine Gun" McGurn is portrayed in this film as "Tim Coogan."
In real life, Danny Cohen owned the club in which Joe E. Lewis first worked. When Lewis defected for more money, Cohen gave mobster Jack "Machine Gun" McGurn (real name: Vincenzo Antonio Gebhardi), a lieutenant in Al Capone's mob, a 25% share in the club in return for his persuading Lewis to stay. McGurn's method of persuasion was the beating which Lewis received.
The song "June in January" was sung by Bing Crosby in the movie using his image behind a screen.