Doyle shot his second straight 5-under 67 to better Tom Watson by two shots in the Senior Slam in St. Augustine, Fla.
Doyle, the seasons top money earner on the Senior circuit, earned an unofficial $300,000 for his victory. He also won this event two years ago.
Senior PGA Championship winner Watson shot 66 to finish runner-up and collect $150,000. U.S. Senior Open champion Bruce Fleisher fired a 65 to finish in third place at 7-under and earn $100,000; while Doug Tewell, who won the Tradition, closed in 67 to finish at 6-under and make $50,000.
Doyle won twice on tour this season, including the Senior Players Championship, which qualified him for this major-winners-only tournament.
The former hockey player who owns a driving range in Georgia led by three strokes as the day began, but watched as Watson got within a single shot twice on the back nine.
Watson missed an 18-foot birdie putt at the 17th hole that would have tied him for the lead, then three-putted from 30 feet on the final hole.