Former MP Pierre Nantel will try his luck under the Parti Québécois (PQ)'s banner the Marie-Victorin riding by-election on Montreal's south shore.
The riding was left vacant after independent MP Catherine Fournier was elected mayor of Longueuil earlier this month.
"We're fortunate to have a candidate that is truly rooted locally," PQ leader Paul St-Pierre Plamondon said in the announcement.
"[He] embodies exactly what we want to embody. That is to say, he brings people together in the name of credible responses to the environment, language, and culture."
Nantel was elected in 2011 with the NDP in Longueuil — Saint-Hubert and again in 2015 before his party ousted him in 2019, after it got wind Nantel was in talks to join another party.
The former MP later joined the Green Party when he ran as a candidate in the same riding and was defeated.
On Thursday, St-Pierre Plamondon announced that he would not be a candidate in the by-election in Marie-Victorin.
The riding, located in the Vieux-Longueuil borough, has been a PQ stronghold since 1981.
Premier François Legault said a by-election would be held in the riding after Christmas, but the exact date has not yet been announced.
The by-election must take place within six months of Fournier's official departure, as stipulated in article 130 of the Election Law.