Doyle earned $217,500 for his second Senior PGA Tour victory of the season, and moves to within $40,590 of Fleisher for the top spot on the 2001 money list.
'We've got three or four guys who carry the weight out here,' Doyle said, 'and when you beat one of those guys, it's extra special.
'I'm thrilled to be in that company.'
In a battle between the two most recent major champions, both men finished regulation at 11-under-par 205. Doyle shot 5-under 67 on Sunday; while Fleisher, who had a bogey and a double bogey over his first three holes, shot 69.
Fleisher, the U.S. Senior Open champion, and Doyle, the Ford Senior Players champion, each parred the first playoff hole, the 18th.
They then moved to the par-4 10th, where Fleisher made a 15-foot birdie putt to put the pressure on Doyle. However, Doyle responded by making his putt from four feet.
At the third extra hole, the par-4 17th, both men hit their second shots into the greenside bunker. Doyle blasted out to four feet before Fleisher hit his shot about 20 feet past the hole.
Fleisher missed his par putt, while Doyle made his.
'I don't get to beat (Fleisher) that often,' said Doyle. 'Everytime you go up against Bruce, you have to play pretty much a mistake-free round.'
Full-field scores from the State Farm Senior Classic