Born in New York, he graduated from the United States Military Academy at West Point, 9th in the Class of 1860. Commissioned into the 1st U.S. Artillery, he served in combined Batteries E & G, 3rd U.S. Artillery, throughout the Civil War with the Army of the Potomac, eventually as part of the famed U.S. Horse Artillery Brigade. Despite his rapid advance in the regular army, having been promoted to captain in 1862, he took a volunteer commission and served as colonel of the 2nd New York Volunteer Cavalry until the end of the war.