When World War II started in 1939 Szell was in the U.S. on his way to Europe after having toured Australia. He stayed in the U.S. and settled with his family in New York City. At first he earned a living as a teacher, but he soon began to get invitations to conduct. He conducted the NBC Symphony Orchestra in 1941. From 1942 he often conducted the Metropolitan Opera, and the following year he appeared with the New York Philharmonic. In 1946 he became a naturalized citizen of the United States.