All but forgotten today due to a lack of surviving footage, robust William Duncan was one of the leading serial and Western stars of the 1910s. A former instructor at McFadden's Physical Culture School and later the owner of his own bodybuilding academy, the Scottish-born, U.S.-educated Duncan gained nationwide notoriety touring vaudeville with the famous wrestler Sandow. He became an actor/director with the Selig Polyscope Company in 1910, and his personal stock company would soon include the novice Tom Mix. Leaving Selig in favor of the bigger Vitagraph in 1915, Duncan directed and starred in The Fighting Trail (1917), the first of ten action serials that would make him both immensely popular and comfortably wealthy. A Fight for Millions (1918) co-starred brunette Edith Johnson, who would soon become Mrs. Duncan offscreen. They made an additional seven serials together and then retired. Duncan came out of retirement in 1935, and would portray Buck Peters, Hopalong Cassidy's Bar 20 boss, in five Westerns released by Paramount between 1935 and 1939.