Benjamin O. Davis, Sr., was born in Washington, D.C., on July 1, 1877. He entered the military service on July 13, 1898, during the War with Spain as a temporary first lieutenant of the 8th United States Volunteer Infantry. He was mustered out on March 6, 1899, and on June 18, 1899, he enlisted as a private in Troop I, 9th Cavalry, of the Regular Army. He then served as corporal and squadron sergeant major, and on February 2, 1901, he was commissioned a second lieutenant of Cavalry in the Regular Army.