Director Jules Dassin made the film while in the process of being blacklisted. Fox studio chief Darryl F. Zanuck told him it may be the last film he'd ever direct, so he should shoot the most expensive scenes first so the studio wouldn't be able to blacklist him until it was completed.

The character Harry Fabian (Richard Widmark was far more sympathetic in this movie than he was in Gerald Kersh's novel. in which Harry was not above pimping his girlfriend and blackmailing. Also, unlike the Harry Fabian in the film, he was a Brit masquerading as an American in order to impress others.

According to Twentieth Century-Fox publicity at the time of the film's release, a total of 54 different London locations were used.

Richard Widmark stated in an interview that he lost a great deal of weight during the production because of the all running he had to do.

Director Jules Dassin claims people have accused him of lifting elements from John Huston's The Asphalt Jungle (1950), even though Dassin only saw Huston's film long after this film was made, and Huston's film premiered only a day before Dassin's.

There are two versions of the film: the British release and the International/American release. There are a few scenes added to the British version and the scores of the two films are entirely different.

Jules Dassin has stated that he did not read the novel "Night and the City" until after the film was completed.

Labeled by critic Thom Andersen as an example of "film gris", a suggested sub-category of film noir incorporating a left-wing narrative.

There's a scene when Harry Fabian goes on the run and Kristo sends Yosh to spread the word there's a 1000-quid bounty on Harry. Yosh can be seen driving by a theater's marquee advertising the showing of Escape Me Never (1947).

In one of Harry's trips to London at night, a theatre advertises the play, "The Third Visitor". This play would be made into a film the year after this film was released, The Third Visitor (1951).

Finnish censorship visa # 2043 delivered on 19-9-1950 (banned). New decision on 9-4-1965 (K-16).