Marlene Dietrich and Zsa Zsa Gabor share a title card ("Guest Starring Marlene Dietrich, Zsa Zsa Gabor"). Gabor has a bit part; she is onscreen for twenty seconds at most. Dietrich has a pivotal role and appears in four crucial scenes including the finale.

Orson Welles claimed to have only read "Badge of Evil" by Whit Masterson, the novel on which the film was based, after he completed the film. He based his rewrite of the screenplay upon Paul Monash's initial treatment.

Orson Welles claimed to have only seen this film once, at the one screening that the studio provided prior to his writing of the memo.

Orson Welles dubbed Joseph Cotten's line, "Now you can strain him through a sieve."

Orson Welles initially despised the title "Touch of Evil", having had nothing to do with its conception. Over the years, however, he grew to like it, and eventually considered it the best title out of all his films.

Orson Welles originally wanted Lloyd Bridges in the role of "Menzies". The studio refused, and instead cast veteran actor Joseph Calleia. Welles was pleased with this new choice, because he had seen Calleia on stage as a child and thought he was very talented.

Orson Welles said that this was the most fun he'd ever had filming a picture, unlike most of his Hollywood films, because he wasn't troubled by studio interference (until after he completed the picture, anyway), he was given a healthy budget and he was working with a crew of some of his favorite actors on a script that didn't involve as much symbolism and all-out cinematic tricks as something like Citizen Kane.

Orson Welles shot predominantly at night in order to fend off meddlesome studio suits.

Orson Welles stated that his goal with the film was to infuriate the audience with the plot, in much the same way that Howard Hawks did with The Big Sleep. The story became even more confusing once the studio re-cut the picture.

Orson Welles wanted the credits to appear at the end of the film so as not to distract the audience from the long (and famous) initial tracking shot. He finally got his wish with the 1998 alternate version, dubbed 'the directors's cut'.

Orson Welles wanted to shoot the film in Tijuana, Mexico, but the studio refused his request.

Orson Welles was fired as director during post-production, and the film was recut contrary to his wishes. Before his death, he left instructions on how he wanted the film to be edited, and in 1998 a version was made the way he intended.

Orson Welles was initially offered to only act in the film, but when Charlton Heston demanded that Welles direct, the studios offered him the director's chair as long as he wouldn't get paid for the writing or directing, only for his original salary as an actor.

Orson Welles was originally hired only to act in the film, but due to a misunderstanding, Charlton Heston understood that Welles was to be the director. To keep Heston happy, producer Albert Zugsmith allowed Welles to direct. Welles made major changes to the already-completed script, including changing Heston's character from a white district attorney to a Mexican narcotics agent, changing Janet Leigh's character from Mexican to American, and changing the setting of the movie from a small California town to a Mexican-American border town..

Orson Welles was said to have based the drug scenes on his own experiences, with the Grandi kids' use of marijuana symbolizing his own indifference towards the legality of the drug, and the violent use of heroin representing his feeling that anything harder than that was just "suicide", as he once put it.

Janet Leigh broke her left arm before filming commenced, but appeared nonetheless. The arm was in a cast, hidden from the camera, for many scenes. In the more revealing motel scenes, the cast was removed for filming, and re-applied afterwards.

Janet Leigh's agent initially rejected her participation in this film due to the low salary offered without even consulting the actress. Orson Welles, anticipating this, sent a personal letter to the actress, telling her how much he looked forward to their working together. Leigh, furious, confronted her agent telling him that getting directed by Orson Welles was more important than any paycheck.

According to Orson Welles, Universal didn't want the film to be screened at the Brussels World's Fair, but the head of distribution had such faith in the film that he submitted it without the studio's knowledge. He was subsequently fired once it was awarded the top prize.

According to the autobiography of Charlton Heston, the scene where Vargas and Schwartz discuss getting proof against Quinlan while driving along in Vargas' convertible marks the first time in film history when a scene with dialogue was shot in a moving car. Rather than using a fake car in front of a projection screen, director Orson Welles had the car rigged with the necessary camera and audio equipment and instructed the two actors how to activate it.

After filming was completed, Orson Welles left to go to Mexico to continue filming his version of "Don Quixote". It was during this time that Universal asked for cuts, and since he wasn't around, they began cutting it themselves.