He was a Member of the National Assembly of Quebec (MNA), and the leader of the Action démocratique du Québec (ADQ), from 1994 to 2009.

Dumont obtained a Bachelor of Arts in Economics from Concordia University in 1993, and completed some graduate work at the Université de Montréal.

Dumont and Liberal party insider Jean Allaire played a central role in the creation and development of the Action démocratique du Québec (ADQ) in 1994.

[4] In subsequent years, however he changed positions on the issue, arguing that the sovereignty question had been decided and that Quebecers had no desire to revisit it.

Since the 1998 provincial election, Dumont has distinguished himself primarily for his stances on economic issues, which are generally considered to be right of centre in the context of the predominantly social-democratic Quebec political scene.

He advocates the payment of a cash allowance to parents who do not wish to make use of the province's $7 a day daycare program, changes to the provincial health system that would allow private for profit health care and private health insurance alongside the public system, the abolition of school boards, the encouragement of private education, a tougher criminal justice system, reductions in the size of the provincial bureaucracy, and the repayment of the province's $127 billion government debt.

In the 2007 Quebec election, the ADQ won 41 seats with 31% of the popular vote, and formed the Official Opposition in the National Assembly.

[5] On October 23, 2008, two ADQ MNAs, André Riedl and Pierre-Michel Auger, crossed the floor to the governing Liberal Party, embarrassing Dumont.