Papagos, commissioned in 1906, saw his first service in the Balkan Wars (1912–13). He took part in the Greek invasion of Turkey (1919–22), won promotion to the rank of major general (1927), and became corps commander and minister of war (1935); the following year he was named chief of staff. Although at the time of the Italian attack on Greece (October 1940), he conducted, as commander in chief, a passive, basically defensive campaign, he nonetheless succeeded in driving the Italians back into Albania. His defenses soon crumbled, however, under the later German onslaught (April 1941), and he was taken to Germany as a hostage. Liberated in 1945, he directed postwar operations in Greece against communist guerrillas and was appointed field marshal in 1949.

In May 1951 Papagos resigned as military commander in chief to form a new political party, the Greek Rally, which soon became the strongest political force in Greece. Enjoying wide popularity and modeling himself after Charles de Gaulle, Papagos led his party to a decisive victory in the elections of November 1952 and became premier. He died in office.