Though Donald has yet to win one of golf's four major titles, his two PGA Tour victories and remarkable consistency were enough to edge out American Webb Simpson.
Donald, who triumphed at the WGC-Accenture Match Play Championship in February before coming from five shots behind to win the season-ending Disney Classic on Sunday, totalled 60 points.
Simpson, also a double winner on the 2011 PGA Tour, earned 56 points while fellow American Nick Watney was third with 48 points.
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Donald, who recorded an eye-catching 14 top-10 finishes in 19 PGA Tour starts this year, also won the coveted Vardon Trophy for the season's lowest adjusted scoring average.
The 33-year-old Englishman ran away with the award, his average score of 68.86 relegating Simpson (69.25) to second place with American world number four Steve Stricker (69.36) third.
Donald is widely regarded as the front-runner to scoop PGA Tour player of the year honours, which will be announced in early December.
Based on balloting of tour members, this award is perhaps the most cherished by the players as it reflects their standing among their peers.
Vying with Donald for this award are Americans Simpson, Keegan Bradley, Stricker and Nick Watney -- all of them double champions on the 2011 PGA Tour.
While PGA Championship winner Bradley is the only one among them to have landed one of the four majors this season, Donald has been the game's leading player and triumphed four times worldwide during 2011.
