- Actor-Inspired Element: James Cagney drew on his memories of growing up in New York's Yorkville, a tough ethnic neighborhood on the upper east side, just south of Spanish Harlem.. His main inspiration was a drug-addicted pimp who stood on a street corner all day hitching his trousers, twitching his neck, and repeating, "Whadda ya hear! Whadda ya say!" Those mannerisms came back to haunt Cagney. He later wrote in his autobiography, "I did those gestures maybe six times in the picture. That was over thirty years ago - and the impressionists have been doing me doing him ever since."
- Cagney's other inspiration was his childhood friend, Peter "Bootah" Hessling, who was convicted of murder and "sent to the electric chair" on July 21, 1927. The night Bootah was executed, Cagney was "playing in a Broadway show" and "wept" upon hearing of his friend's death.
- Banned in China: Because of the controversy over gangster films, the film was banned outright in Denmark, China, Poland, Finland, and parts of Canada and Switzerland.
- Completely Different Title: In Sweden, the film was called "Panik i gangstervärlden", meaning "Panic in the Gangster World".
- Fatal Method Acting: Averted. In those days, real bullets were used, as the use of squibs hadn't been perfected yet. While filming the shoot-out in the warehouse, James Cagney, wary from a previous experience on The Public Enemy, refused to stand in front of a window as ordered and let a machine-gun expert fire away at him. During a take, a hail of live bullets blew through the window pane where Cagney was supposed to put his head.
- Never Work with Children or Animals: The Dead End Kids were an example of the former, throwing off other actors with their ad-libbing and even terrorizing Humphrey Bogart on the set. It took James Cagney, who grew up on the streets of Yorkville, to set them straight.
- Those Two Actors: This was one of many films that James Cagney made with Pat O'Brien and the first of three he made with Humphrey Bogart.
- Unintentional Period Piece: In part due to the "Mister Sandman" Sequence.
Trivia / Angels with Dirty Faces