Graham Greene, on whose novel the movie is based, said that it was "the only good film ever made from one of my books by an American director."
Franz Waxman re-used his title music for this movie in Dark Passage (1947). The same music was also used over the titles in To Have and Have Not (1944).
Reviews were so disastrous that Warner Brothers decided to add extra scenes with Humphrey Bogart and Lauren Bacall to The Big Sleep (1946) in order to build up her role and hopefully limit the damage to her image.
This is famously the movie where Howard Hawks said Lauren Bacall let her voice get high again, and as a result no one liked her in it. Curiously enough there is no sign of this in the movie.
According to a contemporary article in Daily Variety, Warner Bros. intended the film to star Humphrey Bogart and Eleanor Parker after it acquired the film rights to the novel.