He went on to participate in the China Relief Expedition during the Boxer Rebellion and as an observer in the Russo-Japanese War. During World War I, Hayes was promoted to colonel and first served as a special agent for the State Department in France and later held an administrative assignment on the Italian front. After the war he was promoted to brigadier general. Hayes was a member of the Ohio Commandery of the Military Order of the Loyal Legion of the United States by right of the service of his uncle, Lieutenant Colonel J.T. Webb, as an officer in the Union Army during the American Civil War. Rank and organization: Lieutenant Colonel, 31st Infantry, U.S. Volunteers. Place and date: At Vigan, Luzon, Philippine Islands, December 4, 1899. Entered service at: Fremont, Ohio. Born: March 20, 1856, Cincinnati, Ohio. Date of issue: December 17, 1902. Citation:  Pushed through the enemy's lines alone, during the night, from the beach to the beleaguered force at Vigan, and returned the following morning to report the condition of affairs to the Navy and secure assistance.