Born Nov. 11, 1913, in Coimbra. Leading figure in the Portuguese and international labor movement. The son of a lawyer.
Cunhal studied law at the University of Lisbon from 1931 to 1935, where he organized an illegal group, the League of Friends of the USSR, and a section of the International Organization for Aid to Fighters for the Revolution.
In 1935 he joined the Portuguese Communist Party and headed an illegal Communist student organization. From 1935 to 1940 he was general secretary of the Union of Portuguese Communist Youth. From 1936 he was a member of the Central Committee of the Portuguese Communist Party (PCP). In 1936–37 he fought in the Spanish Civil War of 1936–39.
From 1938, with interruptions, he was a member of the Secretariat of the PCP Central Committee. Cunhal was active in reorganizing the party from 1940 to 1941 to strengthen and broaden its ties with the masses.
During 1937–38, in 1940, and from 1949 to 1960, Cunhal was in prison, where he was tortured. In January 1960 he escaped with a group of PCP leaders from the fortress of Peniche. In 1961 he became general secretary of the Portuguese Communist Party.