Alphonse Juin, son of a gendarme, was born in Bône, Algeria, on 16 December 1888. After his studies in Constantine and later in Algiers, he was admitted to Saint-Cyr in 1909. He graduated at the head of his class –the "de Fès" class, in 1912 – the same year as Charles de Gaulle. He chose to join the Algerian Tirailleurs. Assigned to Morocco at the end of 1912, Second Lieutenant Juin took part in the pacification operations in the country.
On 3 August 1914, Germany declared war on France. Lieutenant Juin joined the front with the Moroccan troops. In September 1914, he took part in the Battle of the Marne. Seriously wounded on the Champagne front in March 1915, he partially lost the use of his right arm. Captain in 1916, he joined the 5th battalion of Moroccan Tirailleurs at the Chemin des Dames. In February 1918, he completed army staff training at Melun before being seconded to the French military mission to the American army in October and assigned to developmental training courses for the liaison officers of the American Expeditionary Force.
He earned the certificate of the École Supérieure de Guerre in 1921 and served in Tunisia before returning to Morocco at the end of 1923, where he took part in the Rif Campaign. He returned to France with Maréchal Lyautey in the autumn of 1925 and worked under his orders at the Conseil Supérieur de la Guerre. Promoted to the rank of Battalion Chief in 1926, he left for the 7th Algerian Tirailleurs regiment in Constantine the following year.
In 1929 he was put in charge of the military staff offices of the Resident-General of Morocco, Lucien Saint, and played an active role in the last phase of the Atlas pacification plan. Promoted to Lieutenant Colonel in March 1932, he became a professor of general tactics at the École Supérieure de Guerre in 1933 before being assigned second in command at the 3rd Zouave regiment in Constantine. He took command of this regiment on 6 March 1935. In June, he was promoted to Colonel. In 1937, he was assigned to the service of the Resident-General of Morocco, General Noguès, and also took courses at the Centre des Hautes Études Militaires.
Named Brigadier General on 26 December 1938, he was assigned to mobilisation at staff headquarters for the North Africa theatre of operations. As the situation in Europe was worsening, he was in Algiers preparing measures relative to raising divisions in Algeria and Tunisia. With the declaration of war in September 1939, he asked to serve in metropolitan France. The following 4 December, he took up command of the 15th Motorised Infantry Division. When the German forces launched their offensive in the west on 10 May 1940, his division entered Belgium, where it fought remarkably at Gembloux on 14 and 15 May. Further to the south, German troops broke through the front at Sedan. Juin received an order to pull back. He successively defended Valenciennes and the outskirts of Lille, providing cover for the retreat 1st French Army toward Dunkirk. He was captured in Lille on 30 May 1940 and imprisoned at Königstein fortress. Named Major General during his captivity, he was released in June of 1941 at Maréchal Pétain’s request as a specialist of North Africa. Named deputy to the Commanding General of the troops in Morocco on 16 July 1941, he was promoted to General of the Army Corps and replaced General Weygand at the head of the North Africa forces on the following 20 November. For the Army of Africa, he pursued the policy adopted by his predecessor: "defence against everybody" (both Axis and Allied forces).
On 8 November 1942, the British and Americans landed in Algeria and Morocco. Juin, who was not informed of the operation, was arrested in Algiers by members of the local resistance movement. The authorities quickly took back control of the city. Juin was freed and intervened to obtain a cease-fire between the landing forces and the French troops. Back in the war on the Allied side, the Army of Africa then participated in taking back France’s national territory, with Tunisia as the first theatre of operations. During this campaign (November 1942 – May 1943), General Juin commanded the French Army Detachment and was named Army General on 25 December 1942. He held the position of acting French Resident-General in Tunisia starting on 8 May 1943. During the summer, he set up the French Expeditionary Corps that he led into the Italian Campaign. After several successful battles, on the Pantano in December 1943, on the Rapido and at Belvedere in January 1944, he was victorious at Garigliano on 13 May, opening up the way to Rome for the Allies. He then moved north to Sienna and northern Tuscany. Juin left the French Expeditionary Corps and Italy in August.
Named general chief of the national defence staff under General de Gaulle, Head of the Provisional Government, he entered liberated Paris on 25 August alongside the General. As France’s liberation continued, he dedicated himself to reorganising the French armed forces to enable them to play a full role at the end of the operations. At the same time, as a military expert, he carried out many missions, notably to Moscow in December 1944 where he took part in the negotiations on the future Franco-Soviet pact and to the United States in April of 1945 for the foundation of the United Nations. In April 1946, General Juin was sent to the Far East to negotiate the withdrawal of Chinese troops occupying northern Indochina.
In 1947, Juin returned to North Africa where he was appointed to the position of France’s Resident-General in Rabat, Morocco. The situation in the Far East continued to deteriorate, however, and in October 1950, the government sent him on a new mission to Indochina. Inspector general of the French armed forces in January 1951, he took on command of the allied forces in the Central Europe sector the following September under the Atlantic Alliance. His functions put him in the centre of domestic and international problems: France’s place in the Atlantic Alliance, the debate on the European Defence Community (EDC), the movement of the North African countries toward independence, the war in Indochina, etc. At the same time, he was promoted to the rank of Maréchal de France on 7 May 1952 and was admitted to the Académie Française on 26 June.
In February 1957, he published his first book, “Le Maghreb en Feu”, and then dedicated himself to writing his Memoires and various books.
Maréchal Juin died on 27 January 1967.
He had received the Grand Cross of the Legion of Honour and held the Médaille Militaire, the War Cross 1914-1918, the War Cross 1939-1945, the War Cross for Foreign Operational Theatres, the Colonial Medal for Morocco and Tunisia, as well as many foreign decorations.