Most of the movie was shot on location, and the area really was so dilapidated that set designers barely had to do anything to make it look so apocalyptic.
According to veteran TV writer and producer Steven Bochco, this film served as one of the inspirations for his ground breaking series Hill Street Blues (1981).
The experiences of real life former NYPD Detectives Thomas Mulhearn and Pete Tessitore served as inspiration for the original screenplay by Heywood Gould. It is reported that Paul Newman spent some time with Mr. Mulhearn, getting into character for Officer Murphy. Thomas and Pete, along with other ex-cops helped add to the authenticity of the experiences documented in "Fort Apache the Bronx".
According to her autobiography, Pam Grier, who played the murderous hooker, was originally considered for the female lead part of Isabella.
Rachel Ticotin's character "Isabel" was partly inspired Thomas Mulhearn's long-time Puerto-Rican/Cuban girlfriend Venus Castaño. She worked in a medical office and lived in situations similar to "Isabel" at the time of writing and production. Venus Castaño actually auditioned for the role despite the personal connection to the character. Though, she wasn't cast, she appeared as an extra in several scenes, along with Thomas Mulhearn and their daughter Elizabeth.