 He was the only child of Henry Mims and Susan Burr Read of Edgefield, South Carolina.During the United States Civil War, Major Mims served with the Confederate States Army under General John C. Pemberton and saw action in the Battle of Jackson, Champion Hill and Vicksburg Campaign.He served on the staffs of John C. Pemberton and Joseph E. Johnston and shared friendship with Johnson along with continued business interests until Johnson's death in 1891.