The three-time major champion shot a 3-under 69 to finish at 20-under 268 in his debut in the tournament at Horizon Hills Golf and Country Club. Harrington last won at the 2008 PGA Championship.
“Two years is a long time, especially when you’re reminded every week you play,” said Harrington, part of Europe’s Ryder Cup winning team. “It’s nice and very important for me to win. It’s somewhat a monkey off your back.”
It was the Irishman’s third Asian Tour title after wins in Taipei and Hong Kong.
“There’s no doubt that it was my week to win,” he said. “If you had followed me for the four days, I don’t think anyone would have questioned that my name was written on the trophy before the tournament started. … I hit some good shots and had a few breaks.”
Harrington took a five-stroke lead into the final round of the event and tightened his grip with three straight birdies beginning at No. 2, but had two bogeys over his closing three holes.
The 19-year-old Noh retained the Asian Tour Order of Merit lead after a 65. He moved to 5 under for the round through 11 holes, but a bogey on 13 where he found water with a drive ended his challenge.
Lin Wen-tang of Taiwan finished four strokes back in third after a 68 that included a double bogey on the seventh hole.
“Padraig was in good form,” Lin said. “There were no par-5s for him as he played them like par-4s.”