Born in 1824 in Vermont, William F. Smith graduated from West Point in 1845 and served as a topographical engineer until the war. As a brigadier general he fought in the Peninsula campaign, Antietam and Fredericksburg. It was his criticism of Gen. Butler at this point that cost him his command and a promotion. Sent west, he earned Grant's favor by opening up a supply line to the besieged Union army at Chattanooga. In 1864 he was given command of the XVIII Corps.

Smith was the lead element of the Union strike at Petersburg on June 15, 1864. His failure to vigorously attack the Petersburg defenses was a blunder that again cost him a command. He was placed on special duty in July 1864.

Smith resigned in 1867 and spent a good deal of time arguing his service record until his death in 1903.