Barnhardt was commissioned a second lieutenant in the
Sixth Cavalry and served at Fort McKinney, New York, from September 30, 1892, to October 2, 1894. During the
Spanish–American War, he commanded a cavalry troop in the Santiago campaign. After the war, he spent two years at
Fort Leavenworth, in Kansas and then participated in the
China Relief Expedition, followed by four years in the
Philippines. From 1907 to 1909, he was in
Cuba and from 1909 to 1912 was adjutant of the 15th Cavalry. Barnhardt then did General Staff duty from 1913 to 1916 and was on the Mexican border. In 1916, he was also serving with the Quartermaster Corps. He commanded the
329th Infantry at
Camp Sherman, in Ohio, and was in France with the American Expeditionary Force after the
American entry into World War I. On August 1, 1918, he was promoted to brigadier general of the national army and assigned to the 178th Brigade in France and Germany. From 1921 to 1925, after arriving back in the United States, Barnhardt was a General Staff colonel, and from 1925 to 1927 he commanded the Sixth Cavalry. He also commanded the Military District of Washington from July to September 1927, and his last assignment was the command of the 22d Infantry Brigade in Hawaii. ==Awards==