It was the first time in a close final round that Wadkins lined up for a go-ahead putt.
'It was a pretty simple putt,' Wadkins explained. 'It was downhill and I knew it was going to get there. I've been lucky making nice putts to win tournaments the last couple of years, and I did it again today.'
After trailing Doyle by one stroke overnight, Wadkins shot a 4-under 68 in the final round and made seven birdies in his last 10 holes while he, Eduardo Romero and Loren Roberts were taking aim at Doyle's slim lead.
'It was just a good day. It was fun,' said Wadkins, who finished at 15-under 201.
Doyle had a 30-foot birdie putt at the 18th come up about eight inches short and closed with a 2-under 70. He ended at 14-under 202, missing the chance for a second win at the tournament where he claimed his first Champions Tour title in 1999.
Romero shot a 68 and tied Mike Reid (69) for third place at 13-under 203.
Mark O'Meara, playing in the final group in just his second Champions Tour start, struggled early but still managed a 1-under 71. He fell back into a tie for fifth place with Roberts, the 2006 champion, who had a final-round 66.
The duo came in at 12-under 204.
Wadkins now has four career wins on the Champions Tour -- three more than his better-known older brother, Lanny, although Lanny also owns 21 PGA TOUR titles, including the 1977 PGA Championship.
Bobby Wadkins had a shaky front nine Sunday, posting a birdie at No. 4 but then making two bogeys over the next three holes.
He began to turn things around with three consecutive birdies around the turn, eventually pulling within one shot of Doyle when he made a 4-foot birdie putt at the 11th and Doyle missed a 5-footer for par.
Wadkins bogeyed the 12th to fall two back and was still behind by a pair of shots even after making a 3-foot birdie putt at the 13th. He went birdie-bogey-birdie over the next three holes and was tied for the lead after Doyle bogeyed the 17th.
At the 549-yard, par-5 18th Wadkins was 40 yards ahead of Doyle after their second shots -- but his ball was in 3-inch-high rough next to a sand trap.
He caught a break, though, when Doyle couldn't get any closer than 30 feet on a 90-yard approach shot. Wadkins pitched within 14 feet, watched Doyle miss his birdie try, and then made his for the win.
It was the first time in five tournaments this season that Wadkins finished better than 26th.
'I worked hard this offseason on my back and my swing. The first four weeks I played decent, I just never got anything out of it,' Wadkins said. 'I got off to a good start this week and hung in there.'
D.A. Weibring and Andy Bean both shot 69 to finish tied for seventh place at 11-under 205. Fuzzy Zoeller (67) and Don Pooley (66) were a shot further back at 206.