The Senior British Open winner at Carnoustie in July for his first victory on the 50-and-over tour, Broadhurst made a 6-foot birdie putt on 18 after running his first attempt past the hole.
The 51-year-old Englishman finished with a 4-under 68 for a one-stroke victory over Bernhard Langer and playing partner Kevin Sutherland. Langer birdied the last for a 66, and Sutherland birdied the final two holes for a 70.
Joe Durant bogeyed the 18th - lipping out a 3-footer - for a 67 to finish fourth at 9 under.
The seniors played alongside boys and girls from The First Tee programs throughout the country.