'I'm tickled pink,' said Wadkins, who pocketed $240,000 for the win. 'I needed to take care of one. It's been a long time and I've played well and finally closed the deal.'
Floyd shot his age on Sunday with an 8-under-par 63. He finished alone in second place at minus-9.
'That was fun,' said Floyd, who has not won since 2000. 'I was so focused with what I was doing. That's what happened today - I felt like I was totally with it.'
Wadkins has not won since his Champions Tour debut at the 2001 Lightpath Long Island Classic. That win came 10 days after his 50th birthday and made him the youngest winner in Champions Tour history.
Had Wadkins not pulled it out in the end and Floyd went on to victory, he would have been the oldest winner on the elder circuit by almost eight months.
'Jeez, I don't know what Raymond was doing on Mother's Day over there shooting a 63,' joked Wadkins. 'He can win next week.'
Loren Roberts posted a 2-under 69 and tied for third place with Tom Watson (67), Scott Simpson (67) and Craig Stadler (70) at 7-under-par 206. Roberts, a three-time winner already this season on the Champions Tour, collected $88,000 for his joint third-place finish and moved over the $1 million mark for the year.
Wadkins bogeyed the sixth hole, but the biggest story on the course was Floyd.
He collected back-to-back birdies from the third, then did it again from the seventh.
Floyd birdied the par-5 11th, then drained a 7-foot birdie putt at 12. He collected his third birdie in a row from 8 feet at No. 13 and drained an 11-footer at the 14th for four straight. Floyd converted a 6-foot birdie putt at 15 to polish off five birdies in a row and took over the lead of the championship at 10 under par.
Floyd fell back to 9 under thanks to a three-putt bogey at the 16th, but Wadkins had to chase him.
Wadkins knocked his approach inside 3 feet to set up birdie at the 10th. That got him to 9 under par and he did not make it easy on himself getting into the clubhouse.
He drove through the fairway at the 14th, pitched out and hit his third at the par-4 hole to 6 feet. Wadkins holed the clutch par putt, then made a nice par from the cart path at 15.
At the par-5 17th, Wadkins hit a smart drive, then laid up down the left side to give himself the best angle at the flag. He spun his approach back to 5 feet and holed the birdie putt to move one past Floyd.
Wadkins parred 18 to get to the winner's circle.
'I had a couple of bad breaks on the back side, but I hung in there,' said Wadkins. 'I was just hitting the ball extremely well this week. I putted real good the first day.'