McIlroy, three strokes down at the turn after leading by one after 54-holes, eagled the par-5 10th and added two clutch birdies to overtake Phil Mickelson and Rickie Fowler at rain-drenched Valhalla for his fourth major triumph.
"It is the most satisfying," McIlroy said. "To win it in this fashion and this style, it means a lot. It means that I know that I can do it, I know that I can come-from-behind. I know that I can mix it up with the best players in the world down the stretch in a major and come out on top." (After split with Wozniacki, McIlroy begins his true romance with golf)
The 25-year-old from Northern Ireland fired a final-round 68 to finish 72 holes on 16-under par 268 to defeat US left hander Mickelson by a stroke with Fowler and Sweden's Henrik Stenson two adrift.
"It's great to have that in the memory bank and great to have in the locker going forward," McIlroy said.
McIlroy, coming off a British Open triumph just three weeks ago at Hoylake, won his other major crowns at the 2011 US Open and 2012 PGA Championship, giving him four wins in the past 15 majors.
He has matched Ernie Els and Ray Floyd, moved within one major win of Mickelson and Seve Ballesteros and shocked himself at how rapidly it all happened.
"I thought winning the Open a few weeks ago had sort of put me on a higher level in this game, but then to win a fourth major here, to be one behind Phil, one behind Seve, level with Ernie, level with Raymond Floyd, I mean, I never thought I'd get this far at 25 years of age," McIlroy said.
"It's something that I'm just going to have to come to terms with in a way. I was happy being a two-time major champion coming into this year and all of a sudden I'm a four-time major champion.
"It has just been an incredible run of golf and I just couldn't be more proud of myself or happier with where my game's at."
- Masters, Faldo new goals -
McIlroy has said he has no designs on the record 18 majors won by Jack Nicklaus, instead setting more modest goals like Nick Faldo's modern-day European career best of six majors.
"I've got to take it one small step at a time," McIlroy said. "The two next realistic goals are the career Grand Slam and trying to become the most successful European player ever.
"They are the next goals and hopefully, when I achieve those, I can start to think about other things. But right now, that's what my focus is."
McIlroy became the fourth-youngest man to win his fourth major title, older only than Nicklaus, Woods and Young Tom Morris.
But his trophy case still lacks the green jacket symbolic of supremacy at Augusta National in the Masters, a void he will try to fill next April.
"By the time January 2015 rolls around, I'll be thinking of Magnolia Lane and I'll be thinking about trying to slip on a green jacket for that fifth major," McIlroy said.
- "Rory Slam" in 2015? -
Should he win the 2015 Masters, McIlroy could win a fourth major in a row at next year's US Open at Chambers Bay, a "Rory Slam" like the "Tiger Slam" four in a row by Woods that ended with a 2001 Masters title.
"We'll take it one step at a time. It's 242 days away. We can't get ahead of ourselves here," McIlroy said.
"I'm playing some great golf at the minute and I want to keep this run going as long as I can, and hopefully I'm in just as good form heading into Augusta next year and have a chance to win the career Grand Slam.
"If that happens, then we'll turn our attention to Chambers Bay and I'll try and get the job done. But first things first."
For now, the torch as golf's most dominant player has clearly passed from Woods to McIlroy.
"It's a great place to be in, to be one of the faces of golf," McIlroy said. "You have to welcome it and I don't think you can see it as a burden.
"It's a big responsibility but at the same time, I feel like I'm up to the task of handling it well.
"At 25, I didn't think I would be in this position so I'm trying to just take it day by day and try and take every victory like this in my stride and keep going forward."