"I never really believed in destiny, but I'm starting to believe it," said the Japanese player, who lost to Zach Johnson in a playoff at the AT&T Classic last year.
Imada birdied the 18th hole at TPC Sugarloaf to finish with a 67 and tie Perry, who shot a 69, at 15-under-par 273, forcing the playoff, also on No. 18.
Imada won with a par after Perry's second shot bounced off a tree behind the green, rolled across the green and landed in water.
"I must have been pumped up because it hit the tree trunk over there and shot across the green into the water," Perry said. "So what are you going to do?"
Imada won $990,000.
Camilo Villegas was third, one shot back at 14-under, after a final-found 66 that included birdies on five of the last seven holes.
Jonathan Byrd (70) was fourth at 13-under.