When William Knox Stark was born on 5 October 1892, in Missouri City, Fort Bend, Texas, United States, his father, Francis Marion Stark, was 36 and his mother, Susan Josephine Hillhouse, was 38. He married Rosa Jane Slater on 19 May 1915. They were the parents of at least 2 sons and 1 daughter. He lived in Sutherland, Lincoln, Nebraska, United States in 1920 and Routt, Colorado, United States in 1930. He died in 1930, in Yampa, Routt, Colorado, United States, at the age of 38, and was buried in Yampa, Routt, Colorado, United States.