Just 20 months after losing his wife Heather to cancer, the 39-year-old from Dungannon edged out dogged Dutchman Robert-Jan Derksen (73) by a stroke after a nerve-filled 73 left him on eight under par.
In a dramatic finale to a fascinating final round, Clarke blew a two-stroke lead with bogeys at the 16th and 17th before his closing birdie gave him his his first win since his wife passed away.
As the vital putt fell, Clarke punched the air in a V for victory salute and hugged caddie Phil Morbey, who was carrying the bag for only the third time.
After his first win since 2005 and his first on the European Tour for five years, Clarke was visibly emotional as he dedicated his 11th European Tour win and his 17th worldwide to his sons Tyrone and Conor.
He's also on course for his sixth Ryder Cup appearance after jumping to 14th in the money list and to 28th in the Ryder Cup Points List.
Relieved and delighted, Clarke said: "This one is very special. It’s been the toughest one of all of them, to try and get back up to where I feel my golf should be.
"Although I messed about a bit at the end there, it’s just nice to win again. It’s a really, really good feeling."
Asked if he doubted that he would ever win again, Clarke said: "There’s always doubt. There’s been more frustration than there has been doubt but I’ve had so much support from so many people – all my close friends, they know who they are, have been ‘Go on Darren, keep going, keep going’.
"Sometimes it’s a big black hole there and it’s not easy to see through it. You know, they have been very supportive of me and I’ve been very grateful. It’s nice to be out the other side again."
It could have been a tragic afternoon for Clarke, who wobbled dangerously down the stretch before avoiding a play-off with that closing birdie putt.
With the rest of the field playing for third, Clarke and Derksen were tied at the top on nine under par entering the back nine before the Ulsterman edged a stroke clear after a superb approach to six feet at the 10th.
The Dutchman had holed a series of vital par putts to stay in touch and while he did it again at the 12th, he made what looked like a fatal error at the par-three 14th only to see Clarke let him off the hook.
After finishing on a steep downslope through the green, the two-time European Tour winner chipped too strongly and found a water hazard.
He gathered himself to sink a six-footer for a double bogey but Clarke, who had also missed the green, bogeyed as well.
The Ulsterman looked odds on to go three clear at the 16th when his rival drove deep into the trees.
But he walked off the green just one clear ahead after Derksen scrambled his par-four from six feet and watched Clarke woefully miss a three footer for par.
Another bogey at the 17th, where Clarke was disturbed by a camera click and pushed his tee shot into trees, set up a dramatic finale.
But Clarke came out of top by playing the hole in a carbon copy of his opening hole heroics in the 2006 Ryder Cup at the K Club.
With Derksen driving through the fairway into sand, Clarke blasted his drive down the middle and then hit a towering iron over the flag after his rival's clipped seven-iron flew through the back of the green.
Derksen played a superb recovery to tap in distance but rather than lagging his slick, downhill putt to the holeside for a certain play-off, Clarke grabbed his destiny with both hands.
Reflecting on a flurry of emotions down the stretch, Clarke said: "Everything has happened there. You know, I was pretty much in control all day and then, not having been there for quite some time, the thoughts started racing.
"I got ahead of myself and in this game you do that, you pay the penalty and that’s what happened me for a couple of holes.
"I was thinking of things which happened in the past, stuff with Heather and the boys, and I just lost my concentration and made some silly mistakes and this game punishes errors like that."
As for his winning putt, Clarke confessed that he had no intention of coming up short and leaving himself a testing three or four footer.
He said: "Robert played such a fantastic pitch there on 18 I thought I’d give it a chance. So I did and it went in. Sometimes things are meant to happen and sometimes they’re not and I guess today was my day.
"I was thinking give it a run at the hole. I wasn’t going to lag it up there three or four feet. Give it a run at the hole.
"You know, I’ve putted well this week – I didn’t put well today – but I gave myself a chance at the last hole there. I hit it really solid and it was tracking nicely from six feet out. Sometimes they are meant to go in."
Reflecting on his errors with the putter on the back nine, when he let Derksen off the hook, Clarke denied that he had taken his foot off the accelerator.
He said: "Not really because this golf course is so good that if you do hit good shots you have the chance of making birdies and Robert was playing pretty well, so he was going to have his chances.
"The other side of that is if you play a poor shot you pay a penalty and, as you saw, I paid the penalty a little bit for my couple of poor ones and made it a lot more exciting than I’d planned to do."
On his three-foot miss on the 16th and subsequent mistakes, he added: "The brain went dead as it does frequently. I just thought, hit it left edge and I just tried to get my head there before the ball went in. I played the next couple of holes like an amateur, really.
"On the 17th tee a camera click at the top of backswing - right in the middle of it. I guess my concentration wasn’t good from what I’d just done on the previous green.
If I was really focussed on what I was doing, I would have backed off, stopped and started again. It’s easy now in hindsight but it wasn’t quite as easy at the time."
Peter Lawrie finished strongly with a two-under par 70 giving him a share of ninth place but Rory McIlroy and Gary Murphy frittered away the cash.
McIlroy slipped from tied 15th to 27th after five bogeys in a six-hole stretch saw him come home in 40 for a 76 while Murphy remained outside the top 115 who retain their cards after a 75.