This song tells a story about the notorious gangster Al Capone and his men having a shootout out with the police. As you can see from the comments below, there is plenty of debate as to whether or not the story is true. Mitch Murray, who wrote the song, cleared this up when he sent Songfacts the following:
"I'd like to start by thanking your contributors for so many flattering comments regarding 'The Night Chicago Died.' As co-writer of this song, I feel qualified to settle some of the questions posed by those comments. My writing partner, Peter Callander, and I are both British and it's true, we'd never been to Chicago at the time we wrote the song - many other parts of the USA, but not Chicago.
Having been brought up on a tasty diet of American gangster movies, the term 'East Side' usually meant the seamy side of a city. Of course, looking back, it was used about New York, not Chicago. We (actually, I mostly blame Peter because he had the last words on lyrics while I had the last word on the tunes) were obviously a little careless with our research, as we were when we wrote about Al Capone fighting the 'forces of the law' - I really don't think that ever happened; apparently, the cops were nearly all on Capone's payroll.
The song was certainly a work of fiction, and as such, perhaps we should have used fictional gangster names. Still, it's hard to have regrets when your song is #1 in the USA.
Just to put the record straight, Paper Lace was the excellent group who recorded our song, but had nothing to do with the writing - that was our department, as was production of the record. Thank you all, once again, for your interest in 'The Night Chicago Died' Mitch Murray, London, England. (West Side of London)"