The Irishman was a late edition to the tournament after Ernie Els' withdrawal but took full advantage, with a series of accurate iron shots helping him to rounds of 66 and 67 in Bermuda.
The victory was even sweeter for Harrington given he has twice lost out in play-offs at the event traditionally contested between the year's four major winners.
The three-time major champion, who has played Wilson Staff irons for the past 14 years, was delighted to come out on top.
"It was unfinished business for me, having lost two play-offs, so it was nice to come back and win," he said.
Harrington is only the second European winner of the event since its inauguration in 1979, joining Ian Woosnam, who took the title 1991.
"I believe I'm playing really good golf. I see a lot of good things happening and I do believe that I'm turning a corner into a peak. What those peaks are, we'll wait and see," he added.
The 2007 and 2008 Open champion - who uses Wilson Staff FG Tour V2 irons 5-PW, along with FG Tour wedges - converted a series of quality iron shots after the turn, putting enough distance between himself and eventual runner-up Webb Simpson.
After his $600,000 victory, Harrington will be full of confidence as he turns his attention to the closing stages of the European Tour's Race to Dubai. Wilson Staff FG Tour V2 irons are available from stockists at an RRP of £599. For more information, visit www.wilson-staff.com.
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Nick Bonfield joined Golf Monthly in 2012 after graduating from Exeter University and earning an NCTJ-accredited journalism diploma from News Associates in Wimbledon. He is responsible for managing production of the magazine, sub-editing, commissioning and feature writing. Most of his online work is opinion-based and typically centres around the Majors and significant events in the global golfing calendar. Nick has been an avid golf fan since the age of ten and became obsessed with the professional game after watching Mike Weir and Shaun Micheel win The Masters and PGA Championship respectively in 2003. In his time with Golf Monthly, he's interviewed the likes of Rory McIlroy, Justin Rose, Jose Maria Olazabal, Henrik Stenson, Padraig Harrington, Lee Westwood and Billy Horschel and has ghost-written columns for Westwood, Wayne Riley, Matthew Southgate, Chris Wood and Eddie Pepperell. Nick is a 12-handicap golfer and his favourite courses include Old Head, Sunningdale New, Penha Longha, Valderrama and Bearwood Lakes. If you have a feature pitch for Nick, please email firstname.lastname@example.org with 'Pitch' in the subject line. Nick is currently playing: Driver: TaylorMade M1 Fairway wood: TaylorMade RBZ Stage 2 Hybrid: Ping Crossover Irons (4-9): Nike Vapor Speed Wedges: Cleveland CBX Full Face, 56˚, Titleist Vokey SM4, 60˚ Putter: testing in progress! Ball: TaylorMade TP5x
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