Alexandre Cloutier is the third candidate to become leader of the Parti Quebecois.
The MNA for Lac St. Jean launched his campaign on Monday in his riding, surrounded by supporters and family members.
He promised that in the weeks to come he would present concrete ideas on how to revitalize the PQ and Quebec.
The party had its worst electoral showing in decades earlier this year, when Premier Pauline Marois led the party to defeat.
Cloutier, 37, has been an MNA since 2007, and was Intergovernmental Affairs minister in the Marois cabinet.
Bernard Drainville and Martine Ouellet have already officially declared their candidacies, while other expected candidates such as Jean-Francois Lisée and Pierre Karl Peladeau have yet to do so.
