(orig. William Christensen; b Brigham City, Utah, 27 Aug. 1902; d 14 Oct. 2001)
US dancer, choreographer, teacher, and ballet director. He studied with his uncle Lars Peter Christensen in Salt Lake City, with Stefano Mascagno and L. Albertieri in New York and with Fokine, in whose company he later danced. Between 1927 to 1932 he toured the vaudeville circuit with his brothers Lew and Harold, then opened a school in Portland, Oregon, out of which grew the Portland Ballet. From 1937 he danced with the San Francisco Opera Ballet, becoming ballet master and choreographer in 1938. When the opera disbanded its ballet company during the Second World War, he and his brother Harold bought the opera's ballet school and established the independent San Francisco Ballet. He choreographed the first American full-length versions of Coppélia (1939), Swan Lake (1940), and Nutcracker (1944). He left San Francisco Ballet in 1951 to become Professor of Dance at the University of Utah. In 1952 he founded the Utah Ballet, later Ballet West (1968).