[1] He represents the electoral district of Rosemont as a member of Québec solidaire.

Following the 2022 provincial election, he became the opposition critic for Health; Ethics; the Metropolis; and Sports, Leisure and Outdoors.

His journalistic career began with La Voix de l'Est, a newspaper in Granby.

Marissal later wrote for Le Soleil in Quebec City, covering the affairs of the National Assembly.

He later worked for La Presse in Montreal, where he continued to cover politics while also authoring the newspaper's weekly wine column.