Following the success of The Hunchback of Notre Dame in 1923, Lon Chaney was once again given the freedom to create his own make-up as the Phantom, a habit which became almost as famous as the films he starred in. Chaney pulled his eyeballs out from their sockets with thin wires, so that his eyes appeared to bulge out and their sockets became very deep. He then kept his eyes in their bulged-out position with wires and painted his eye sockets black, giving a skull-like impression to them. He also pulled the tip of his nose up and pinned that in place with wire, enlarging his nostrils with black paint, and putting a set of jagged false teeth into his mouth to complete the ghastly deformed look of the Phantom. Although nowhere near as elaborate as his make-up for Quasimodo in The Hunchback of Notre Dame, it was no less painful, and no less effective either. When audiences first saw The Phantom of the Opera, they were said to have screamed or fainted at the scene where Christine pulls the concealing mask away, revealing his skull-like features to the audience (but not, for a few seconds, to Christine).
Chaney's appearance as the Phantom in the film has been the most accurate depiction of the title character, based on the description given in the novel, where Erik the Phantom is described as having a skull-like face with a few wisps of black hair on top of his head. As in the novel, Chaney's Phantom has a full facial deformity present since birth, as opposed to the partial facial disfigurement caused by acid or fire (depending on the adaptation) seen in later adaptations of The Phantom of the Opera.
It is in the appearance of the Phantom that Lon Chaney is most associated with in the mind of the public.