While filming the climactic ballroom scene, Erich von Stroheim noticed an extra whose costume was not adjusted to his liking. He stepped off the high camera platform on which he was standing, fell, and broke his leg. He directed the rest of the film from a reclining chair while his leg healed.
Author Scott Eyman, in his book "Lion of Hollywood: The Life and Legend of Louis B. Mayer", says that Mae Murray was "abusive, borderline delusional, and served as the primary inspiration for the character of Norma Desmond in Sunset Blvd. (1950)". When she was later in difficulties, Louis B. Mayer "refused to add her to his list of pensioners".
One of the most expensive scenes to be filmed, a champagne-fueled orgy with numerous under-dressed chorus girls, was cut for censorship reasons.
Erich von Stroheim did not want to have John Gilbert play Danilo, and the two got into a big fight when filming began. Soon afterward, they made up and became close friends.
Joan Crawford and Clark Gable both appear as extras in this film. According to author William J. Mann, in his book "Behind the Screen: How Gays and Lesbians Shaped Hollywood 1910-1969", future costume designers Irene and Walter Plunkett also appear as dance partners.
Erich von Stroheim: [prostitutes] Danilo brings Sally to a brothel, where a wild party is in progress, with the intent to seduce her.
Erich von Stroheim: [janitors] A street cleaner is shown outside the brothel where Danilo brings Sally.