A long-time member of the Italian Socialist Party (PSI) and close aide of Bettino Craxi, Intini was spokesman of the PSI and representative of the party in the Socialist International.

Intini led the electoral list of PSI in the region Liguria after Sandro Pertini and was elected three times in the Chamber of Deputies from 1983 to 1994.

In 2001, he was elected again a deputy in the single-member district of East Genoa, a position he maintained until 2006.

He served twice in the centre-left coalition-led government: from 2000 to 2001 as undersecretary to the Foreign Affairs and from 2006 to 2008 as Deputy Minister.

Among his many books, there is a history of this newspaper, whose editors were Leonida Bissolati, Benito Mussolini, Antonio Gramsci, Pietro Nenni, Giuseppe Saragat, Pertini, and Craxi.