His first screen credit was the starring role in the 1937 movie Love Is on the Air, and by the end of 1939 he had already appeared in 19 films. Before the film Santa Fe Trail in 1940, he played the role of George "The Gipper" Gipp in the film Knute Rockne, All American; from it, he acquired the lifelong nickname "the Gipper. Reagan's favorite acting role was in 1942's Kings Row, in which he recites the line, "Where's the rest of me?," later used as the title of his 1965 autobiography. Many film critics considered Kings Row to be his best movie.