After graduating from USMA, Hunter was commissioned and assigned frontier duty with the Fourth Cavalry. He participated in various conflicts during the American Indian Wars from 1877 to 1984. During the Spanish American War, Hunter was wounded at San Juan Hill. In 1903, Hunter was stationed in the Philippines to suppress the insurrection. He was stationed again in the Philippines from 1911 to 1914 at Fort McKinley. Hunter returned to the United States on June, 1914 and was assigned to serve as Inspector General in Chicago, Illinois until August, 1917.