He was an Action démocratique du Québec (ADQ) Member of the National Assembly of Quebec (MNA) for the electoral district of Trois-Rivières from 2007 to 2008.

[citation needed] Proulx first ran in the 2003 election in Laviolette, but finished third with 14 per cent of the vote behind Liberal incumbent Julie Boulet.

[3] Even though he was considered one of the ADQ's most effective parliamentarians and benefited from a high approval rating from his constituents, Proulx lost his seat as a result of the 2008 election.

[6] Proulx campaigned on behalf of local Conservative candidate Claude Durand during the federal election of 2008.

[7] Durand finished a distant second against Bloc Québécois incumbent Paule Brunelle in the district of Trois-Rivières.