Ghislain Lebel has been an activist in the Quebec independence movement since his teenage years, having been part of the Rassemblement pour l'indépendance nationale, the Mouvement souveraineté-association and the Parti Québécois since its early days.
Lebel ran as a Bloc Québécois candidate in the district of Chambly in the 1993 election and won.
On August 20, 2002, he crossed the floor and sat as an Independent, because of his sharp criticism of the Approche commune, an agreement with the Innu people signed by the Government of Quebec, then led by Bernard Landry and the Bloc's brother sovereigntist party, the Parti Québécois.
He entered the Parti Québécois leadership campaign in 2005, in which he defended a more traditional form of nationalism and ideas relatively less to the left than the other social democratic candidates.
Lebel voted for the Action démocratique du Québec (ADQ) in protest in the 2007 Quebec election.