When William Sylvester Jackson was born on 22 February 1854, in Richmond, Wayne, Indiana, United States, his father, William Leonard Jackson, was 33 and his mother, Louisa J. McCoy, was 24. He married Sarah Ruth Stafford on 5 January 1878, in Knox, Nebraska, United States. They were the parents of at least 4 sons and 3 daughters. He lived in Marion Township, Linn, Iowa, United States in 1860 and Western Township, Knox, Nebraska, United States in 1880. He died on 21 March 1925, in Crawford, Dawes, Nebraska, United States, at the age of 71, and was buried in Crawford, Dawes, Nebraska, United States.