The son of a blacksmith in a Croatian village, Tito fought in Russia with the Austro-Hungarian army in World War I and was captured by the Russians. He served with distinction in the Red Army during the Russian civil war of 1918 to 1920. Several years later Broz returned to Croatia and, while a metalworker, became a prominent union organizer. He was (1929–34) imprisoned as a political agitator. In 1937 the Comintern assigned to him the reorganization of the Yugoslav Communist party, and in 1941 he emerged as a leader of Yugoslav partisan resistance forces after the defeat and occupation of Yugoslavia by the Axis Powers. It was then that he adopted the name Tito.
Although the core of his partisan army was Communist, Tito's rapidly growing forces included many non-Communists. Despite the opposition of the Yugoslav government in exile, which supported the Serbian resistance leader Draža Mihajlović, Tito's army and its successes soon eclipsed those of Mihajlović and his chetniks. Among the causes of his success were his swift guerrilla tactics, his own magnetic personality, and the appeal of his political program—a federated Yugoslavia—to the non-Serbian elements of the population. Although they cooperated at first, Tito and Mihajlović soon clashed.
By 1943, Tito headed a large army and controlled a sizable part of Yugoslavia, centered in Bosnia. Tito was supported from the first by the USSR, but in 1944 he also received the full support of Britain and the United States. In Nov., 1944, after the liberation of Belgrade, he negotiated a merger of the royal Yugoslav government and his own council of national liberation, and in Mar., 1945, he became head of the new federal Yugoslav government.
Already the virtual dictator of Yugoslavia, he won a major electoral victory in Nov., 1945, at the head of the Communist-dominated National Liberation Front, whose candidates were the only ones permitted to run in the election. With the opposition abstaining, Tito won almost 80% of the vote. King Peter II was deposed, and a republic was proclaimed (see Yugoslavia).