Angie Dickinson recalled that Ronald Reagan, a conservative Republican, refrained from discussing politics during filming since President John F. Kennedy had been assassinated and the other members of the cast were Democrats.
NBC made a deal with MCA Inc., to produce a series entitled "Project 120", a series of two-hour features made especially for TV. The first one would be "Johnny North", aka "The Killers", but due to the violence and sexual content the title was changed and released in movie theaters.
According to Don Siegel, it was the policy at Universal at the time to shoot the last scene of the film first. On that first day of filming, according to Siegel and Clu Gulager, Lee Marvin arrived late and had been drinking, but because he had no dialogue, the scenes were used as shot.
According to Don Siegel in his biography, Ronald Reagan first refused the role of Browning because he was afraid that playing a bad character would interfere with his image, as an actor or maybe a politician. But Reagan eventually accepted the role after having lunch with Siegel over a salad.
When the news about assassination of President Kennedy was heard at the radio by the crew, the steam room sequence was shot. Then, Angie Dickinson cried hysterically and fainted on the floor. Don Siegel says in his memoirs that he had the most difficulties to help her.
There's a scene in which the camera pans a view of the city and shows a building with a vertical marquee that reads 'BARNETT'S' from top to bottom. In the 1946 version of "The Killers", the role of ex-con Charleston was played by character actor Vince Barnett.