Calixte signed onto the Garde d'Haïti in 1915 as a private, rising in the ranks until he reached the rank of major. During his military career, he trained under the United States Marine Corps. As a major in December 1930, the US gave him one out of the five military departments of the Garde as part of the process of Haitianization within the Garde, as they were withdrawing from their occupation of Haiti. On 1 August 1934, as a colonel, the American Lieutenant Colonel Clayton B. Vogel fully transferred power over the Garde to Calixte. Calixte played a part in the assassinations of other military officers. Following the Parsley Massacre of 1937, Calixte was falsely implied in a plot to overthrow president Sténio Vincent, as many officers had disagreed on the official Haitian reaction to the massacre and wanted to replace Vincent with Calixte. This ended in Calixte's dismissal by Vincent in 1938 and his replacement with Jules André, a chief of the Garde chosen directly by Vincent. Less than a year later, Calixte escaped to France and then the Dominican Republic.