Ulysses S. Grant, in office 1869-1877
Grant entered the Civil War with the 21st Illinois Volunteer Infantry Regiment. On March 2, 1864, President Lincoln promoted Grant to lieutenant general, giving him command of all Union Armies, answering only to the president.
Rutherford B. Hayes, in office 1877-1881
Hayes served with the 23rd Regiment of Ohio Volunteer Infantry and was injured at the Battle of South Mountain on Sept. 14, 1862. He was promoted to brigadier general in October 1864 and brevetted major general.
James Garfield, in office March 4, 1881-Sept. 19, 1881
In August 1861, Garfield received a commission as a colonel in the 42nd Ohio Infantry regiment. He later served as chief of staff to Gen. William S. Rosecrans. Garfield was the 20th president of the United States, serving from March 4, 1881, until his assassination later that year.
Benjamin Harrison, in office 1889-1893
Indiana Governor Morton commissioned Harrison as a colonel on Aug. 7, 1862, with the newly formed 70th Indiana. On Jan. 23, 1865, President Lincoln nominated Harrison to the grade of brevet brigadier general of volunteers.
William McKinley, in office 1897-1901
McKinley enlisted as a private in the newly formed Poland Guards in June 1861, which was consolidated into the 23rd Ohio Infantry. Just before the war’s end, McKinley received his final promotion, a brevet commission as major.