A lawyer since 1999, Sébastien Proulx has practiced law in various firms. He also held various political offices, such as councillor, MP and minister.

He was elected MP for Trois-Rivières and appointed House Leader in 2007 and 2008.

He returned to politics in 2014 by becoming Director of Strategic Planning for Prime Minister Philippe Couillard and he was elected MP for Jean-talon from 2015 to 2019. He was notably a member of several ministerial committees and appointed minister of Families and minister of Education during this mandate.

He is the author of Québec libre est un Québec qui sait lire et écrire with Septentrion, published in 2018.

He is now Director of Governmental and Institutional Relations - Public Policy for the Desjardins Group.