The 28-year-old capped a near-flawless week with a final round of seven-under-par 65 for a facile 11-shot victory over the golfer who succeeded him as the Masters winner this year, Bubba Watson.
"It's been a while and I have been knocking on the door for some time. Then I had injury," last year's runner-up Schwartzel, hindered last year by a rib injury that affected his swing, said after winning at 25-under 263 at the Amata Spring Country Club.
"It's really nice to come back and play some decent golf again."
Looking back at the barren 20 months since winning the 2011 Masters, Schwartzel said: "I played some really good golf after the Masters for almost close to a year when I came close a few times. Then I got the injury and that put me back. I had a bad year actually.
"The last month and half has been pretty good and it's nice to finish the year with a nice win here," said Schwartzel, who made just one bogey in the entire tournament.
"I got off to a nice start and I just kept going. Obviously the golf course suits my eyes and it was nice to play some good golf out there."
Watson matched Schwartzel's 65 to finish 14-under 274 in the $1 million Asian Tour event.
"I didn't have my best stuff on Friday and Saturday. I made a lot of mistakes. Schwartzel played pretty good," Watson said.
"It would have given me a chance to scare him but I didn't have my best in the previous two days."
The American shared second place with local favourite Thitiphun Chuayprakong, who signed off with a two-under-par 70.
Spaniard Sergio Garcia finished fourth on 12-under. (Reporting by Amlan Chakraborty in New Delhi; editing by Justin Palmer)