Sir Dirk Bogarde considered retiring from acting after making this movie, which he found to be a draining experience.
According to an interview given by Charlotte Rampling on the National Public Radio program "Fresh Air," the scene where she dances and sings topless in a Nazi outfit was the first scene filmed.
According to writer and director Liliana Cavani, Charlotte Rampling (Lucia) declined doing another take of a fight scene between her and Sir Dirk Bogarde (Max) because many of the blows he threw were real.
The budget, which had been paid for by the Italian distributor, ran out near the end of the shooting of the film's interiors at Cinecittà in Rome. To ensure the film's completion producer Robert Gordon Edwards instructed editor Franco Arcalli to create a rough cut of the best scenes that had been shot, which he presented to an American colleague who worked at Les Artistes Associés (the French arm of United Artists). On the basis of the rough cut the company agreed to pay for the filming of the exterior scenes in Vienna in exchange for French distribution rights.
Thanks to his critically acclaimed work in such films as Joseph Losey's The Servant (1963) and two by Luchino Visconti, The Damned (1969) and Death in Venice (1971), Sir Dirk Bogarde had become somewhat typecast and took some time off, refusing scripts that would cast him in stories of decadence, degeneracy, or Nazism. However, after viewing with much pleasure Liliana Cavani's TV film Galileo (1968) at his home in France, he remembered he had a script from her for The Night Porter (1974) down in his cellar. He then retrieved the script and read through it that night. He was attracted to the central relationship between the porter and the camp survivor, especially after he discovered the script was based on real events. He called Cavani the next morning to accept the part.