 Lang became a naturalized citizen of the United States in 1939.He made twenty-three features in his 20-year American career, working in a variety of genres at every major studio in Hollywood, and occasionally producing his films as an independent.Lang's American films were often compared unfavorably to his earlier works by contemporary critics, but the restrained Expressionism of these films is now seen as integral to the emergence and evolution of American genre cinema, "film noir" in particular.