Several incidents in the film are based on actual testimony given by captured mobsters. The meeting in the restaurant with the Italian mobster and the dead man's hand sequences are based on the recollections of various New York gangs.
A number of scenes were cut from the film for pacing reasons as the original cut of the film was closer to 3 hours long. Of the scenes cut, the most notable included an entire subplot featuring Frankie and Jackie killing Irish mob bosses together. This subplot was to enhance the relationship between Frankie and Jackie but, in the end, it didn't make it into the final film. To this day, the only footage that remains of these scenes can be seen in some Orion Home Video trailers.
Director Phil Joanou introduced his then-girlfriend Uma Thurman to actor Gary Oldman on the set, and she became Oldman's second wife shortly after the film premiered. The marriage only lasted 18 months before Uma filed for divorce in March 1992.
Sean Penn and Robin Wright became a couple during the filming of this movie, had two children over the next three years, broke up, then got back together before finally marrying in 1996. They eventually divorced in 2010.
When Frankie goes for a sit down with Borelli, the restaurant they are in is the same restaurant that was used several times in the hit TV show The Sopranos (1999).