Peter Ustinov would later say that director Mervyn LeRoy gave him the perfect insight as to how to play Nero. LeRoy told him, "I see Nero as a guy who plays with himself nights."
Elizabeth Taylor: an extra
The film made its debut on network television after having been shown for years on local television stations, as most films were prior to 1961.
One immediate problem they encountered with the lions was that when they were released from their cages, they found the arena so hot, they'd immediately retreat back into their cages. Director Mervyn LeRoy overcame this problem by having several costumes filled with meat.
Cinecitta simply didn't have enough power to cope with the filming so generators were shipped over from English studios. They even requisitioned a generator from a decommissioned Italian warship.
10 handcarved chariots were made specially for the film.
Claude Rains and Fredric March were considered for the part of Petronius.
The narrator is an uncredited Walter Pidgeon.
Over 30,000 thousand extras appear.
There are 110 speaking parts in the film.
The movie's huge box office success was credited with saving MGM from bankruptcy.
Kathleen Byron was considered for the role of Lygia.
Clark Gable turned down the role of Marcus Vinicius, because he thought the costume would make him look ridiculous.
Stewart Granger actively sought the lead role, but was unwilling to commit to a long term contract with MGM.
The film represented a hollow victory for MGM studio chief Louis B. Mayer, since it turned out to be his final big-budget production. Produced for $7 million, it was MGM's largest grosser since Gone with the Wind, but Mayer was forced out of his job prior to its release.