For the hundred-year-old look, Lon Chaney built up his cheekbones and lips with cotton and collodion. The ends of cigar holders were inserted into his nostrils, and his long fingernails were constructed from strips of painted film stock. He used fish skin to fashion an Oriental cast to his eyes and gray crepe hair was used for the mustache and goatee. The makeup procedures took from four to six hours to apply.
According to a later interview with script supervisor Will Sheldon, Lon Chaney tested the makeup design for this film by getting on a Los Angeles streetcar and riding it from one end of the line to the other, changing seats occasionally and holding a bag of laundry. After this, he was confident that the makeup would be convincing on-screen.
Anna May Wong's character's name, Loo Song, is an Anglicization of her own Chinese given name, Liu-Tsong.
"Mr. Wu" features the most screen time Renée Adorée has in any of her surviving films - 50 of its 91 minutes.