In those years, he began to attend the Civic Library, reading popular novels of authors like Victor Hugo, Edmondo De Amicis, Émile Zola and Eugène Sue.

[citation needed] Before the beginning of World War I, he approached the Italian Socialist Party and in 1913 he was enrolled in the Faculty of Law of the University of Turin.

Terracini was elected Deputy and vice-president of the Constituent Assembly in 1946 and became president after the resignation of Giuseppe Saragat the following year.

Terracini was favourable to the alliance with the socialists in the Popular Democratic Front, and after the shooting on Togliatti in July 1948, he presented a no-confidence motion to the government led by the Christian Democracy, which he believes has the moral and political responsibility on the attack to the Communist leader.

[citation needed] Terracini was very critical with Nikita Khrushchev for his report on the war crimes committed by Stalin, which he argued the secretary of the CPSU was too soft with his predecessor.