Ulysses S. Grant's appointment as Commander-in-Chief by Abraham Lincoln in 1864. Painted by Thure de Thulstrup (1848 -1930). Ulysses S. Grant (1822-1885) was the 18th President of the United States and the leading Union general during the American Civil War (1861-1865). A career soldier, he graduated from the United States Military Academy at West Point and served in the Mexican-American War. Under Grant, the Union Army defeated the Confederate military and effectively ended the Civil War with the surrender of Robert E. Lee's army at Appomattox. Grant served two consecutive terms as President after the war and during the turbulent Reconstruction period that followed.