Born in Trois-Rivières, Quebec, Aubin has a diploma in geography from Université Laval and a degree in music and education from the Université du Québec à Trois-Rivières.

At the time of his election, he had been a teacher at the Séminaire St-Joseph for nearly 25 years.

After the 2015 election, Aubin was appointed the NDP critic for International development and La Francophonie in the 42nd Canadian Parliament.

[3] In the 2017 NDP leadership election, Aubin initially supported Peter Julian,[4] then switched his support to Guy Caron after Julian withdrew from the race.

[5] Aubin lost his seat in the 2019 federal election, falling to fourth place.