In December 1939 Juin took command of the 15th Militarized Infantry Division in France. In May 1940 he and his troops performed well in Belgium and northern France, covering the British retreat to Dunkerque (Dunkirk) and fighting at Lille until their ammunition ran out. At the end of May German troops captured Juin, who at the insistence of General Maxime Weygand was repatriated to North Africa in June to command all French troops in Morocco. Immediately, Juin secretly began building up his forces so that they could defend North Africa against German or Italian incursions. He had no advance knowledge of the Anglo-American North African landings in November 1942, but in late November he was instrumental in persuading Admiral Jean Darlan to order a cease-fire.
Juin, who headed the French Army Detachment from late November, subordinated his command to that of British Lieutenant-General Kenneth Arthur Noel Anderson in the Allied campaign to liberate Tunisia, which succeeded in May 1943.
Transferring to Italy, in late 1943 Juin's French Expeditionary Force of Moroccan and Algerian troops, part of U.S. Lieutenant General Mark Clark's Fifth Army, fought spectacularly in Italy's difficult rugged mountains, outflanking the Germans in the Apennines to enable an Allied breakthrough at Monte Cassino in May 1944 and capturing Siena and Florence in July. Juin hoped to follow up these successes by driving north and attacking German forces around the Danube River, but his forces were withdrawn from Italy in July 1944 to join Operation anvil, the invasion of southern France. In August 1944 de Gaulle appointed Juin chief of staff of national defense.
From 1947 to 1951 Juin was resident general in Morocco before spending five years as commander in chief, North Atlantic Treaty Organization (NATO) Land Forces, Central Europe, a position that NATO Supreme Commander and General of the Army Dwight D. Eisenhower requested him to fill. Named a marshal of France in 1952, Juin retired from active duty in 1956. In 1961 he was dropped from the Supreme Defense Council and banned from visiting Algeria after he broke publicly with de Gaulle's position on the bitter Algerian struggle for independence. Later the two men renewed their friendship. Juin died in Paris on 27 January 1967.
Bamberg, James. British Petroleum and Global Oil, 1950-75: The Challenge to Nationalism. Cambridge: Cambridge University Press, 2000.; Crémieux-Brilhac, Jean-Louis. Les Français de l'an 40. 2 vols. Paris: Gallimard, 1990.; Goutard, Adolphe. "Marshal Alphonse Juin." Pp. 596–611 in The War Lords: Military Commanders of the Twentieth Century, edited by Michael Carver. Boston: Little, Brown, 1976.; Ordioni, Pierre. Tout commence à Alger, 1940–1945. Paris: Éditions Albatros, 1985.