Subsequently, he was the regional secretary of the PCI in Sicily, where he distinguished himself for his war against any kind of mafia.

In 1986, Occhetto was appointed as national coordinator of the PCI and became its secretary in 1988, succeeding Alessandro Natta.

He responded by declaring the Communist state experience over, and persuaded the PCI to dissolve and refound itself as a democratic socialist party, the PDS.

This political shift, known in Italian politics as the Svolta della Bolognina (the name derives from the celebration of a partisan battle in World War II), during which he announced that the PCI would change its name, logo, and orientation, was accepted by approximately 70% of the members at the 20th National Congress held on 8 February 1991.

In 1994, Occhetto challenged and was defeated by Silvio Berlusconi in the 1994 Italian general election, leading the Alliance of Progressives; because of this loss, he resigned as party secretary.