He wasn't. The stereotyped Black chauffeur in the Charlie Chan series was played most often by Willie Best, who specialized in sleepy, under-motivated servant types and was, I believe, known by the sobriquet "Sleep 'N' Eat". For a marvelous account of his career, and that of Stepin Fetchit and other African-American actors of Hollywood's Golden Age, see film critic Donald Bogle's pioneering study, "Toms, Coons, Mullatos, Mammies and Bucks".