LeBlanc was born in Bathurst, New Brunswick, on August 25, 1967. He is the son of Roméo LeBlanc, who served as Governor General of Canada from 1995 to 1999. LeBlanc attended the University of New Brunswick, where he earned a Bachelor of Arts degree in political science and history. He then went on to earn a Master of Arts degree in international relations from the University of Sussex in England.
LeBlanc began his political career in 1993, when he was elected to the New Brunswick Legislative Assembly. He served in the provincial government for eight years, holding a number of cabinet positions, including Minister of Education and Minister of Finance. In 2008, LeBlanc was elected to the House of Commons of Canada, representing the riding of Beauséjour.
LeBlanc has served in a number of ministerial roles in the federal government. He was Minister of Fisheries and Oceans from 2015 to 2019, and Minister of Northern Affairs from 2019 to 2021. In 2021, he was appointed Minister of Intergovernmental Affairs, Infrastructure and Communities.
LeBlanc is a member of the Liberal Party of Canada. He is married and has three children.