William Turner was born into slavery in Albemarle County, Virginia, either in 1828 or on April 1, 1832, to William and Leah Turner. His owner moved him to Pike County, Missouri, at some point before the Civil War. He married Dollie Winston in a slave ceremony, and they had fourteen children together: Georgianna, Leah, William (Billie), Edward, Emma, Sallie, Shelton, Noble, Lewis, Ester, Saw, Dollie, Barbara, and another unnamed child. Several died in childhood, and only eight remained alive by 1915.

Turner enlisted in the Union army on March 14, 1864, in Pike County, Missouri, for a period of three years. He mustered in as a private in Company F of the 68th USCT Infantry Regiment on March 25 at Benton Barracks in St. Louis. His enlistment record describes him as 5 feet, 1/2 inches tall, with black hair, black eyes, and a black complexion. The regiment remained in St. Louis until April 27, when the army transferred it to Memphis, Tennessee. The men remained there until February 1865. He injured his left eye when a piece of a percussion cap flew off, causing partial blindness. The army promoted him to corporal on September 1, 1864, and to sergeant on April 1, 1865. In April 1865, he took part in the Mobile Campaign and helped capture Fort Blakely in Alabama. He spent the next several months in Texas and mustered out in February 1866 in Camp Parapet, Louisiana. 

Turner returned to Pike County, Missouri, after the war. He and Dollie legally married on September 2, 1866, in a ceremony officiated by an African Methodist Episcopal preacher in Lincoln. In 1870, Turner and his immediate family lived in the same household with his parents and his brother's family. In 1880, he and Dollie lived with several of their children and grandchildren. Ten years later, in July 1890, he applied for a pension, citing rheumatism and his wartime eye injury. By 1924, he was receiving $38 per month. Dollie passed away by 1910, and Turner then moved in with his daughter Georgianna. He died in Clarksville, Missouri, on June 4, 1924.