He graduated from the Lycee St. Louis in Paris in 1899 and from the French Naval Academy in 1902.
During World War I he commanded a battery of naval guns on the Western front. In 1929 he became a rear admiral, in 1932 a vice-admiral, and in 1939 a full admiral and commander in chief of French naval forces. After France's defeat in World War II, Darlan joined the Vichy Government as Minister of Foreign Affairs, National Defense and Information. He acted also as vice-premier and led the cabinet. Summoned to Algiers by his son's illness, he was there in November 1942 when the Algerian French leaders, after accepting an armistice, refused to obey Gen. Henri Giraud, first U. S. choice as French African commander. Gen. Mark W. Clark, realizing that Darlan was the only man in Africa that the French would obey, asked him to order the French forces not to resist the planned landing of American troops in Africa. Darlan at first refused to do so without the consent of Marshal Henri Petain, head of the Vichy government, but later, when threatened with imprisonment, he complied. After his dismissal by Petain and after the German invasion of southern France, Darlan signed an agreement with the American officials on November 22, 1942, which made him political chief of the French administration in North Africa. Through his faithful execution of the terms of this agreement, American forces gained access to Dakar without firing a shot and quickly terminated French resistance in the area. American authorities credit him also with doing all he could to get the French fleet out of Toulon. On December 24, 1942, Darlan was assassinated by an obscure, and apparently deranged, young French monarchist, Bonnier de la Chapelle, who was linked to a royalist circle headed by Henri d'Astier.