Calcavecchia, who trailed Bob Tway by one shot coming into the final round, drained five birdies during a six-hole stretch on the front nine en route to the convincing victory.
He finished at 16-under 200, winning by 4 shots at La Vallee du Richelieu Golf Club. His only other victory on senior circuit came at last year's Boeing Classic.
Grabbing sole possession of second was Brad Bryant, who carded a 7-under 65 to end at minus-12.
Tway, meanwhile, registered a 2-under 70, good enough for a third-place tie with Russ Cochran (68) at 11-under par.