Reportedly, Harrison Ford and Josh Hartnett did not get along during production, and neither were very warm with each other when they went out to go promote the movie. Hartnett later revealed in an interview that he and Ford got along better by the end of filming, but said that there were times they would end up just sitting in the car when they were supposed to be doing a scene and neither of them would say anything for like an hour.
Gavilan is based on Robert Souza, who was a homicide detective in the LAPD Hollywood Division and moonlighted as a real estate broker in his final ten years on the job. The scene where a cuffed crook steals the gun from a patrol officer's belt and starts shooting it off in the parking lot actually happened during Souza's tenure.
The subplot of Gavilan trying to sell Jerry Duran's house to Julius Armas is based on Robert Souza's real-life attempt to sell Robert Evans' house to Dodi Fayed, who was in the music business at the time and for whom Souza did bodyguard work.
Lolita Davidovich, who plays escort service madame Cleo Ricard, is actually the real-life wife of director Ron Shelton.
Harrison Ford admitted in a interview that this was the worst film he ever did in his career and that he only did it for the money.
Ron Shelton: [several things happening at once] Joe Gavilan talks with Cleo Ricard while K.C. talks to a talent agency while a suspect grabs a police officer's gun and starts firing it.