Trivia

Frank Sinatra played Detective Joe Leland from the novel "The Detective" by Roderick Thorp. Thorp wrote a sequel ("Nothing Lasts Forever") in which Leland is trapped in a Claxxon Oil Corporation skyscraper after it's taken by German terrorists and must rescue his daughter and grandchildren. Twenty years later the novel was filmed with some changes: the daughter became his wife, Claxxon became the Nakatomi Corporation, Joe Leland's name was changed to John McClane, and the film was released under the title Die Hard (1988). Because of a clause in Sinatra's contract for "The Detective," which gave him the right to reprise his role in a sequel, he was actually the first person offered the McClane role even though he was 73 years old at the time. Also, coincidentally, Bruce Willis (who played McClane) made his movie debut in The First Deadly Sin (1980), walking out of a bar as Sinatra walked in. Additionally, Lloyd Bochner played Dr. Wendell Roberts in this movie. His son, Hart Bochner, played Harry Ellis in Die Hard (1988). Finally, Jacqueline Bisset's then partner, Alexander Godunov, played a villain in Die Hard.

Frank Sinatra was supposed to co-star with his wife Mia Farrow in this film, but a film Farrow was working on was running behind schedule so she refused. Sinatra got so mad that he made the film without her (casting Jacqueline Bisset in the role instead) and served her divorce papers on the set of that film, Rosemary's Baby (1968). When both films were released and Rosemary's Baby performed better at the box office over The Detective, according to Robert Evans's autobiography The Kid Stays in the Picture, a particularly embittered and vindictive Farrow wanted to get back at Sinatra by having Evans post an advertisement in Variety comparing the two films' box office and popularity, but Evans wouldn't.

Frank Sinatra and Ralph Meeker, who appeared in this movie, played the same character (Francis X. "Iron Balls" Delaney) in two other movies. Meeker played him in uniform in The Anderson Tapes (1971). Sinatra played him in plainclothes as a detective in The First Deadly Sin (1980).

Mark Robson was originally set to direct, but Frank Sinatra preferred Gordon Douglas, with whom he had made four previous films.

This film came out two years before Jack Klugman suddenly became a star in the TV comedy The Odd Couple (1970) and eight years before he would be recognized as Quincy, M.E. (1976). Klugman having grown up on the rough streets of Philadelphia, which included work as a street pedlar, Frank Sinatra had a great deal of respect for him, and it was during this period after the Rat Pack that Klugman would become a member of Sinatra's outer circle and be invited to his parties and events in Palm Springs.