In 1914, Carleton was assigned to the Port of Galveston, Texas as embarkation officer, and was responsible for arranging transportation for troops, animals and equipment taking part in the Veracruz Expedition. In 1916, Carleton was promoted to colonel and assigned to the Inspector General's Department in San Francisco. From October 1916 to early 1917, Carleton served with the Inspector General's Department in the Philippines.