Leo Carrillo was descended from a long-established, aristocratic California family. His great-grandfather was the first provisional governor of California, while his father was the first mayor of Santa Monica. His parents wanted him to be a priest, but Carrillo decided to go for an engineering degree while attending Loyola University. A talented caricaturist, Carrillo secured a job as a political cartoonist at the San Francisco Examiner. At the encouragement of his fellow employees, Carrillo decided to parlay his gift for mimicry and dialects into a vaudeville career. He went on to provide comedy relief for several stage plays and musical productions, starring in one tailor-made vehicle, Lombardi Ltd. In films from 1929, Carrillo was frequently cast as excitable, malaprop-ridden Spaniards and Italians; in only a few instances, notably John Ford's The Fugitive (1947), did Carrillo perform in his normal California cadence, sans dialect. From 1950 through 1955, Carrillo co-starred with Duncan Renaldo in the popular TV western series The Cisco Kid, playing Cisco's sidekick Pancho. Though well into his seventies, Carrillo claimed to be in his mid-fifties so that the Cisco Kid company would qualify for insurance coverage. As active in California politics and civic affairs as his forebears, Leo Carrillo was in charge of the annual Fiesta de Santa Barbara, and at one juncture was appointed to the State Park Commission; there still exists a California beach named in Carrillo's honor.