Lon Chaney's make-up was his most extreme yet. A knotted wig, nose putty on the cheeks, some false teeth, and fake eye made up his visage. The final touch was a plaster hump which, contrary to popular opinion, was only about 10-15 lbs and did not cause Chaney any back problems.
Lon Chaney's salary on the film was $2,500 a week. Shooting began in December of 1922, and was completed in June of 1923. Chaney ended up making close to $60,000 plus contract bonuses from the picture, which was the longest shoot in his career.
Wallace Worsley Jr., son of the film's director, said that many of the extras for the massive crowd scenes were recruited in downtown Los Angeles for $1.00 a night and meals. Among them, he said, were a good number of prostitutes, who did a "considerable sideline business" on the sets. Universal also hired 50 Pinkerton detectives and put them among the crowd, and their job was to catch pickpockets and various other thieves among the extras.
A competition was held in 1923 through Universal through various Photoplay music (stock silent music) companies to come up with a theme song for the film. The winner was Maurice Baron, whose characteristic reverie "The Chimes of Notre Dame" was used as the main theme. The original cue sheet to the film came with a copy of the piece for piano, with the suggestion that it be used imperatively.
In many of the scenes where the Hunchback was climbing down it was not Lon Chaney but stuntman Joe Bonomo, who did much stunt work for Universal and later was a prominent bodybuilder.
In order to prepare himself for the role of Quasimodo, Lon Chaney held interviews with people who suffered from various physical deformities. His makeup was so masterful for its time that many film patrons believed that the actor playing the title character truly appeared in real life as he did on film.
Over 750 technicians worked on this film, including 105 electricians. Carpenters and masons constructed the cathedral set, which remained standing until destroyed by fire in 1967.
Poor quality transfers of the film are due to the fact that the film only survives in 16mm form, mainly through Universal's "Show-At-Home" film rental library. About 10-15 minutes of footage still remains missing.
Strict confinement to the brace that held his legs together reportedly caused Lon Chaney to suffer severe pain for the rest of his life. The contact lens he wore in the film also caused tremendous vision loss.
The myth that Irving Thalberg came up with the idea for the movie was dispelled when it was discovered through telegrams and contracts in the collection of Alfred Grasso, Lon Chaney's manager, that Chaney himself suggested not only the story but who would be cast and who would direct. Chaney's original pick for director was actually Frank Borzage, not Wallace Worsley (who had directed several other pictures for Chaney). Erich von Stroheim, Allen Holubar, Chester Withey and Emile Chautard were all considered as well.
This film was the first to use intercom technology to act as a communication device between the director and his assistants during production. Western Electric provided the wireless communication. This is standard equipment on large-scale films today.