Simon Turmel was admitted to the Québec Bar in 1990 and also holds a BA in Political Science from Université Laval (Quebec, Canada). Mr. Turmel was a member of a private law firm, prior to be becoming a member of Hydro‑Québec's, and the Régie de l'énergie's legal services.

He practiced in the field of administrative law, including energy, Indigenous and environmental law. He also led various ministerial offices including those of Justice, Immigration & Cultural Communities, Mines & Wildlife, and Indigenous Affairs. In 2015, he was appointed as Commissioner to the Régie de l’énergie, which is the economic regulatory body for energy in Québec, Canada.

Mr. Turmel has given various conferences on energy law and Indigenous law. In December 2021, he was elected vice-president of RegulaE.Fr, an organization which brings together French-speaking energy regulators, and currently has 31 regulatory authorities from Africa, Europe, the Americas and Asia. Since December 2022, he has been its president.