[1] He represented the electoral district of Tracadie-Sheila as a member of the Liberal Party until 2018, when he did not run for reelection and was succeeded by his former constituency assistant Keith Chiasson.

On October 7, 2014, Rousselle was appointed to the Executive Council of New Brunswick as Minister of Education and Early Childhood Development, and Attorney General.

After being abroad for his studies, he returned to Tracadie, New Brunswick, and was a professor at the Université de Moncton law faculty from 1992 to 2014.

[3] Rousselle has also held various positions in organizations at the provincial, federal, and international level.

Among other positions, he was head of the Bureau des Amériques of the Agence universitaire de la Francophonie, was President of the Council of Canadian Law Deans as well as President of the Association des juristes d’expression française du Nouveau-Brunswick.