 Samuel W. Thornton was the son of Abner and Esther Strain Thornton.His father was a member of a large Scots-Irish and devoutly Presbyterian family that had migrated to Ohio from South Carolina over opposition to slavery During the American Civil War, Samuel joined the Union Army, fighting with Company C, 8th Regiment, Iowa Infantry.He participated in several of the bloodiest battles of the war, including the Battle of Shiloh, Battle of Vicksburg, and Battle of Memphis, where he was shot in the thigh and hospitalized until the end of the war.