Garon turned aside all 29 shots he faced, leading Columbus to its fourth win in five games. The third-year pro remained undefeated in regulation time in 13 career home starts for the Blue Jackets, improving to 8-0-4.
Rick Nash netted his fourth goal of the year to put Columbus on top 12:35 into the game, and Derick Brassard quickly made it 2-0 only 83 seconds later.
Kyle Wilson also scored for the victors.
Carey Price stopped 21-of-24 shots for Montreal, which had their five-game road winning streak snapped. The Canadiens went 0-for-3 on the power play in the setback.