Duceppe is a native of Montreal, and studied political science at the University of Montreal. In his youth he was involved in the Communist Worker's Party, and he later became a trade union negotiator.
In 1990 Duceppe was elected for the newly-formed Bloc Québécois in a by-election in Montreal's Laurier-Sainte-Marie riding.
In 1997 he was elected leader of the Bloc, and consequently became Leader of the Opposition. Later that year, a general election removed the Bloc from official opposition status.
Upon Paul Martin, Jr becoming leader of the Liberal Party of Canada in 2003, Duceppe became the longest-serving current leader of a major party in Canada.