Leblanc first participated in an international tournament when he played for the Canadian national junior team at the 2008 Ivan Hlinka Memorial Tournament in the Czech Republic and Slovakia in August 2008. He led the team with three goals and added two assists for five points as Canada won the gold medal. Leblanc was then invited to try out for the national junior team prior to the 2010 World Junior Ice Hockey Championships, but was one of the last players cut from the team. There was speculation that his participation in the NCAA rather than the Canadian Hockey League (CHL) hindered his chances of making the team, as CHL players had played considerably more games than those in the NCAA. Leblanc also had university exams scheduled around the time of the camp. He was invited to the summer camp the following year in St. John's, Newfoundland and Labrador, and was one of the top scorers at the camp. After the pre-tournament camp in December 2010, Leblanc was named to the final roster for the 2011 World Juniors.