He was born in Turin on 19 September 1898 and died on 11 June 1988.
He graduated in Economics.
In 1922 he joined the United Socialist Party and in 1925 he became a member of the Party Executive. When the Fascist regime came to power he was forced to seek refuge in Austria and subsequently France.
He returned to Italy in 1943 where he was arrested, but managed to escape and resume his underground activities in the Italian Socialist Party for Proletarian Unity, which elected him as a member of the Executive.
He was Minister without Portfolio in the 1st Bonomi Government, and in April 1945 was appointed Italian Ambassador to Paris where, together with De Gasperi, he attended the Peace Conference.
In January 1947 he founded the Italian Workers' Socialist Party (subsequently becoming the Italian Social Democratic Party) and served as its Political Secretary, and while in this post he was appointed Party President until the mid-Seventies, except for the period when he held institutional or governmental offices.
In the 4th De Gasperi Government he was Deputy Prime Minister, and Minister of the Merchant Marine in the 5th De Gasperi Government until November 1949.
He remained Deputy Prime Minister in the Scelba Government and the first Segni Government.
He was Minister for Foreign Affairs in the 1st and 2nd Moro Governments until 28 December 1964, when he was elected President of the Republic.