Every studio in Hollywood turned down Ebbe Roe Smith's script. Producer Arnold Kopelson was getting to the stage of considering cable TV when Michael Douglas came across the script and pronounced it one of the best he'd ever read.
In the scene in which the drive-by car crashes, there is a mural of Christ on the wall. This same mural is also present in Colors (1988), also starring Robert Duvall, in the scene in which the police officer played by Sean Penn, spray paints a kid's face.
Prendergast sings "London Bridge" with his wife on the telephone. The same tune is played by the snow globe that D-Fens buys on Wilshire. The lyrics to the song are "London Bridge is falling down, falling down", a reference to the movie's title. Prendergast also planned to retire to Lake Havasu, Arizona, where the old London Bridge was moved to in 1971.
As Bill Foster gets closer to home, the weapons he acquires become more lethal as do the people from whom he acquires them; First, he acquires a bat from the store owner, then a switchblade from the gang member, a semi automatic from the gang's car and a rocket launcher from the skinhead.
"London Bridge is Falling Down" is heard several times in the film. It is first heard when Robert Duvall sings it to his wife over the phone to calm her down, and the melody is later heard being played in the snow globe D-FENS buys for his daughter.
When D-FENS flips out at Whammy Burger, an old man tries to go out the front door. When the scene ends and it cuts to Detective Prendergast, the same man can be seen (dressed differently) dead-center in the first few moments of the shot.
The Korean American Coalition protested the film for its treatment of minorities as well as the Korean grocer. Because of this and the boycott threats that followed, this movie was banned in South Korea.