King's military career began as a teenager when he was a mounted orderly for the Iron Brigade during the Civil War. After an appointment to West Point by Abraham Lincoln, he graduated in 1866 to receive his commission in the U.S. Army. In 1871 he joined the 5th Cavalry in Nebraska, the same unit for which William F. "Buffalo Bill" Cody was chief scout. He and Cody became friends and remained so for the rest of their lives. Under the command of Gen. George Crook, the 5th Cavalry was active in the plains warfare before being sent to Arizona Territory. There he fought in battles with various grou