Leblanc had 10 points (five goals and five assists) in 50 career games with Montreal. The 23-year-old from Pointe-Claire, Que., made his NHL debut with the Canadiens in 2011-12, leading team rookies in goals and ranking second in scoring.
He appeared in eight games for Montreal in 2013-14, going scoreless with a +1 rating and four penalty minutes.
Leblanc recorded 68 points (34 goals, 34 assists) and had 146 penalty minutes in 163 American Hockey League regular season games with the Hamilton Bulldogs.
"After three seasons with the Canadiens organization we felt that moving forward, the best option for Louis and our organization was to give him the opportunity to pursue his career with another team," said Bulldogs general manager Marc Bergevin.
"Throughout his entire stay with our organization Louis showed great professionalism and a constant desire to improve. We thank him for his contribution and wish him success for the continuation of his career."
Leblanc was selected by Montreal in the first round (18th overall) of the 2009 NHL Entry Draft.