Corporal Puller received orders to serve in the "Gendarmerie d'Haiti" as a lieutenant, seeing action in Haiti. While the United States was working under a treaty with Haiti, he participated in over forty engagements during the ensuing five years against the Caco rebels and attempted to regain his commission as an officer twice. In 1922, he served as an adjutant to Major Alexander Vandegrift, a future Commandant of the Marine Corps.