As vaudeville faded from American popular culture, Harold and Lew joined George Balanchine's new company, American Ballet, in 1935. In 1932, Willam formed a ballet school in Portland, Oregon; in 1937, he was engaged as principal male soloist by San Francisco Opera Ballet. He became the company's ballet master and choreographer in 1938. With his brother Harold, he purchased the company from the Opera in 1942, renaming it San Francisco Ballet. In 1951, Willam retired as director of SF Ballet and moved to Utah, where he started teaching ballet in the country's first university ballet department at the University of Utah. With a group of his students, he founded the Utah Civic Ballet (now known as Ballet West) in 1963; the company remained under Christensen's directorship until 1978.