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.
Poor-quality transfers of the film are due to the fact that it only survives in 16mm form, mainly through Universal's "Show-At-Home" film rental library. About 10-15 minutes of footage still remains missing.
Lon Chaney's make-up was his most extreme yet. A knotted wig, nose putty for warts and on the cheeks, innovative use of cotton and flexible collodion, adhesive tape, 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 lb. and did not cause Chaney any back problems. Chaney's grotesque makeup which took three hours to apply.
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 viewers believed that the actor playing the title character truly appeared in real life as he did on film.
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.