Carroll is perhaps best known for his roles in six Alfred Hitchcock films: "Rebecca" (1940), "Suspicion" (1941), "Spellbound" (1945), "The Paradine Case" (1947), "Strangers on a Train" (1951) and "North by Northwest" (1959). He appeared in more Hitchcock films than anyone other than Clare Greet (1871–1939) (who appeared in seven) and Hitchcock himself, whose cameos were a trademark. As with earlier roles, he was often cast as doctors or other authority figures (such as the spymaster "Professor" in "North by Northwest"). He also appeared in a couple of Charlie Chan films, one being "City of Darkness" (1939) as a shady French locksmith, followed by a role in