Born in
Washington, D.C., Dunlap was appointed a
second lieutenant in the Marine Corps August 8, 1898. He served with distinction in the
Spanish–American War; in the
Philippine–American War Dunlap was attached to the Marine Corps' Philippines regiment from May 1899 to May 1902; during that period served in China from June 25, 1900, to October 9, 1900, and participated in the Battle of Tientsin and in
China, including the
Battle of Tientsin of the
Boxer Rebellion. He was stationed on the Isthmus of Panama, then participated in the
U.S. occupation of Veracruz,
Mexico, in 1914. From September 1915 to February 1917 Dunlap commanded the artillery battalion in Haiti and Santo Domingo and during this period participated in the engagement at Guayacanes, Dominican Republic, on July 3, 1916. Dunlap was assigned to the staff of
General Pershing on 21 May 1917. He returned to the United States in July of that year and in August was detailed to command the Tenth Regiment of Mobile Artillery at Quantico, Virginia. He was absent on temporary foreign shore service for duty with the planning section of the staff of the commander, United States forces operating in European waters from 18 February 1918 to 10 October 1918, when he was detached to command the Tenth Regiment of Marines upon its arrival in France. He was detached from this command on 20 November 1918, having been in command of the Seventeenth Regiment of Field Artillery, United States Army, from 30 October, and participated in the Meuse-Argonne in command of that organization in November until the Armistice. He participated in the march to the Rhine and continued on duty with the
American Expeditionary Forces until 8 February 1919, when he returned to the US. Dunlap studied at the
Army General Staff College from 1920 to 1922, then he commanded the Marine detachment at the American Legation in Peking, China from 1922 to 1924. In 1924 he assumed command of the Marine Corps Schools at Quantico, Virginia, where he remained until January 1928 when he went to Nicaragua to take command of the Eleventh Regiment of Marines and later the Second Brigade. He returned to the United States in August 1929. For his distinguished service as regimental commander during the Meuse-Argonne campaign in
World War I, he was awarded a Citation Certificate by Commander-in-Chief, A.E.F.; the
French Fourragère; and the
Navy Cross. In 1917–18 he analyzed a proposed Allied landing in the Adriatic for Admiral William Sims and concluded that amphibious operations could be successful and there was no absolute advantage for the defender. In 1928 he was awarded the
Navy Distinguished Service Medal and the
Medal of Merit of Nicaragua for his service in that country. Dunlap assumed command of the Marine Corps base at San Diego, California on 25 January 1930. He relinquished that command on 26 December 1930, returning to Washington D.C. to receive an assignment in France. He was posted to France to study Strategy at the
French War College. He and his wife departed the US on 18 February 1931, planning to enroll at the French facility that autumn. ==Death==