He was a founding member of Liga Veneta in 1978–1980, and its national president and practical leader. In 1991 he was a founding member of Lega Nord along with Umberto Bossi and was elected federal president of that party.
In September 1994, after being defeated in a party congress, left the party over disagreements with Umberto Bossi an the new national secretary of Liga Veneta Fabrizio Comencini. He later joined the Federalists and Liberal Democrats and National Alliance, prior to leaving politics.
Rocchetta was married with Marilena Marin, national secretary of Liga Veneta from 1984 to 1994.