It is memorably summed up by Bogart in the film, when he says to the jury who will decide if Nick is executed: “Until we do away with the type of neighborhood that produced this boy, ten will spring up to take his place, a hundred, a thousand. Until we wipe out the slums and rebuild them, knock on any door and you may find Nick Romano.”
Quotation expert Ralph Keyes speculates in his book The Quote Verifier that Motley may have been “recycling street talk” when he wrote the line “Live fast, die young and have a good-looking corpse.”
I did some extensive online searching and found uses and variations of the phrase “live fast and die young” dating back to the early 1900s.
But I didn’t find any uses of the longer saying mentioning a corpse prior to the publication of Knock on Any Door. So, I think Motley’s book probably is the origin of that fatalistic slogan.
Personally, I prefer the Ricky Gervais variation. In an episode of The Office (the original BBC series), he says: “You know that old thing, live fast, die young? Not my way. Live fast, sure, live too bloody fast sometimes, but die young? Die old! That’s the way. Not orthodox. I don’t live by ‘the rules’ you know.”