He studied history and sociology at the Université du Québec à Montréal.
He also received a post graduate certificate in public management at the École nationale d'administration publique.
When Pierre Bourque tried to be elected MNA for the Action démocratique du Québec (ADQ), he became leader of Vision Montréal, which was then the Official Opposition party against Gérald Tremblay.
Lemay had received the support of the SPQ Libre of Pierre Dubuc.
At the time of his assembly nomination, Lemay asked Jean Charest to legislate on climate change, trying to benefit from the recent resignation of Thomas Mulcair.