William Powell graduated from the U.S. Naval Academy at Annapolis, Class of 1893. He served in the Navy during the Spanish-American War, and was commissioned a First Lieutenant in the Marine Corps in 1899, with duty in the Philippine Islands and then in china. He served as Assistant Paymaster throughout much of his career, including World War I. Upon retirement in 1942 after 35 years of service, he was promoted to Brigadier General on the retired list.