McIlroy came out on top following a ballot of PGA Tour members who played in at least 15 official money events during the 2013-14 season and becomes the fourth player to have received the award more than once.
Greg Norman and Nick Price are both two-time winners, while Tiger Woods has been honoured by his peers an astonishing 11 times.
A part of Europe's successful Ryder Cup team at Gleneagles last week, McIlroy claimed three PGA Tour wins during the 2013-14 season - with each of those victories coming in succession during a sensational run of form that saw him return to the summit of the world rankings.
Major triumphs at The Open Championship and US PGA Championship sandwiched a win at the WGC-Bridgestone Invitational.
McIlroy was also the tour's leading money winner, with $8,280,096, having recorded 12 top-10 finishes and did not finish outside of the top 25 in any of his 17 appearances.
The only man to previously complete a PGA Tour season with a perfect record of top-25 finishes was Woods, in 2000.
McIlroy was selected for the prize ahead of FedEx Cup winner Billy Horschel, Martin Kaymer, Jimmy Walker and Bubba Watson.
Chesson Hadley, meanwhile, beat off Victor Dubuisson and Brooks Koepka to take the rookie of the year award.
Hadley, 27, was the only rookie to qualify for the BMW Championship, the third of four FedEx Cup play-off events, landed a maiden title at the Puerto Rico Open in March and registered three other top-10 finishes.