Montoya crossed the finish line nearly five seconds ahead of Kurt Busch, garnering his second career Sprint Cup win and his first victory since June 2007 at Sonoma, Calif., some 113 races ago.
Marcos Ambrose, who won Saturday's Nationwide Series event at Watkins Glen for the third straight year, led for eight laps early on and was in second place until the final lap when Busch passed him. He ended up with a third-place showing.
A.J. Allmendinger was fourth and pole sitter Carl Edwards completed the race in fifth place.
Sprint Cup points leader Kevin Harvick lost ground to Jeff Gordon. Harvick blew a left-rear tire on the last lap to finish 11th while Gordon came in 10th, shaving Harvick's advantage to 185 points.