The coronation of McIlroy as the game's leading player was confirmed in sensational fashion when the exciting Northern Irishman cruised to his second major title by a record eight shots in the PGA Championship at Kiawah Island in August.
Dubbed 'Boy Wonder' in his homeland for the past decade, McIlroy fully justified his other nickname of 'the Celtic Tiger' as he ended the year being showered with virtually every accolade available to him.
He followed in the footsteps of Luke Donald when he became the second player to win the money list titles in both Europe and the United States and he strengthened his position as world number one with an extraordinary run of form.
Long regarded as heir-apparent to Tiger Woods as the game's greatest player, McIlroy has smoothly taken over that role while Woods, despite triumphing three times on the 2012 PGA Tour in a welcome return to winning ways, has had to take a back seat.
The 23-year-old McIlroy is almost certain to be a dominant figure in golf for at least another decade but 14-year-old Chinese Guan Tianlang gave a strong indication of the likely impact from his part of the world well beyond that time frame.
Guan ensured he would become the youngest player ever to compete at the Masters by winning the Asia-Pacific Amateur Championship last month, tantalising proof of the vast golfing potential in the Chinese market.
The world's most populous nation had celebrated another coup just five months earlier when Shanshan Feng, 22, clinched the LPGA Championship by two shots in Rochester, New York to become the first person from mainland China to win a women's major.
Remarkably, Feng was born just five years after the first golf course was opened in China.
There were several other highlights during 2012 with Bubba Watson producing arguably the shot of the year to win the Masters in a two-way playoff and Ernie Els ending a decade-long drought in the majors to claim his second British Open.
THRUST INTO LIMELIGHT
The belly putter was also thrust into the limelight when Webb Simpson, at the U.S. Open, and Els, at Royal Lytham, joined 2011 PGA Championship winner Keegan Bradley as the only players to triumph in the majors using a long putter.
That trend, coupled with the growing number of younger golfers opting to anchor putters to their chin, chest or belly, prompted golf's rulemakers last month to propose a ban on the technique which could come into effect by 2016.
However, McIlroy's stellar play around the world gave golf fans their most stirring memories in 2012.
He recorded four wins on the U.S. circuit among 10 top-10s in just 16 starts before ending the season being named the PGA of America Player of the Year, the PGA Tour's Player of the Year and winner of the Vardon Trophy for the lowest scoring average.
McIlroy clinched the Arnold Palmer Award as the PGA Tour's leading money winner, with earnings of $8,047,952, and was delighted to follow that up with the European Tour order of merit with two events remaining.
"Winning a second major already made it a fabulous season, but then to follow Luke in becoming number one in both Europe and the States is the icing on the cake after a fabulous season," he said.
Hardly surprisingly, McIlroy finished his 2012 campaign on a triumphant note when he won the European Tour's season-ending DP World Tour Championship by two shots in Dubai last month.
"I didn't want the year to just tail off, I wanted to end it in real style," he said after spectacularly making birdies on the last five holes to close with a 66.
While the richly talented McIlroy is a gifted shot-maker, left-hander Watson delivered the 'blow' of the year with a miraculous escape from pine straw to win the Masters in a playoff with South African Louis Oosthuizen in April.
On the second extra hole, the long-hitting American ended up well right and deep in the tree line off the tee from where he had a narrow avenue to the green.
Undaunted, Watson struck a stunning hook off the pine straw with a gap wedge, his ball bending 40 yards in the air to settle 10 feet from the pin before he claimed his first major victory with a two-putt par.
"I got in these trees and hit a crazy shot," said Watson, a self-taught golfer who learned the game by hitting wiffle balls around his house. "I just hooked it up there and somehow it nestled close to the hole."
In June, Watson's good friend and fellow American Simpson clinched his first major title with a nerve-jangling one-shot victory at the U.S. Open after overhauling overnight leaders Jim Furyk and Graeme McDowell.
The following month, 42-year-old South African Els won the British Open at Royal Lytham by one stroke from Adam Scott after the Australian agonisingly bogeyed the last four holes.
Unquestionably the greatest comeback of the year, and perhaps of all time in golf, came at the Ryder Cup in September when Europe overhauled a deficit of 10-6 going into the final day to beat the United States by 14-1/2 points to 13-1/2.
Inspired by the spirit of the late Seve Ballesteros, Europe sent out their best players early and rode a wave of blue numbers to retain the trophy when Germany's Martin Kaymer defeated Steve Stricker one up.
"Seve will always be present with this team," a teary-eyed European captain Jose Maria Olazabal said of his fellow Spaniard, friend and mentor. "He was a big factor for this event, for the European side."
That same month, South Korean Shin Ji-yai romped to a nine-stroke victory at the Women's British Open at Royal Liverpool in England to complete a stunning Asian sweep of the year's four women's majors.
Shin's compatriot Yoo Sun-young won the Kraft Nabisco Championship in a playoff at Rancho Mirage in April and Choi Na-yeon, also of South Korea, claimed her first major title by four shots at the U.S. Women's Open in Kohler, Wisconsin in July.