His second goal this season came in the game's first minute and his third at 7:18 of the second period increased Montreal's lead to 3-0.
Goaltender Christobal Huet stopped 44 of 45 shots for the Canadiens, who have alternated losses and wins over their last six games.
New York prevented Huet's second shutout this season when Mike Comrie scored at 16:10 of the third.
Goalie Rick DiPietro was beaten four times on 33 shots for the Islanders, who had won their previous two games.
The loss also ended their streak of games decided by one goal. They were the first team in NHL history to play seven straight games decided by one goal in regulation time.