The son of an aristocratic family, Hauteclocque graduated from the "École spéciale militaire de Saint-Cyr", the French military academy, in 1924. After service with the French Occupation of the Ruhr and in Morocco, he returned to Saint-Cyr as an instructor. He was awarded the "croix de guerre des théâtres d'opérations extérieures" for leading "goumiers" in an attack on caves and ravines on Bou Amdoun on 11 August 1933. During the Second World War he fought in the Battle of France. He was one of the first who defied his government's Armistice to make his way to Britain to fight with the so-called Free French under General Charles de Gaulle, adopting the "nom de guerre" of Leclerc so that his wife and children would not be put at risk if his name appeared in the papers. He was sent to French Equatorial Africa, where he rallied local leaders to the rebel Free French cause, and led a force against Gabon, whose leaders supported the French Government. From Chad he led raids into Italian Libya. After his forces captured Kufra, he had his men swear an oath known today as the "Serment de Koufra", in which they pledged to fight on until their flag flew over the Strasbourg Cathedral.