'Unbelievable,' said Storm. 'It's just a magnificent feeling. I've been putting too much pressure on myself thinking when is it going to happen. Is it going to happen? Hopefully I can go on to better things.'
Storm posted a bogey-free round on Sunday, including four pars on the final holes, a tough stretch at Le Golf National. He finished at 7-under-par 277 and won by a single stroke over third-round leader Soren Hansen.
Thomas Bjorn and Colin Montgomerie both shared the lead late in the back nine, but struggled down the stretch. Bjorn shot a final-round 69 and Montgomerie had a 70 to tie for third place with Simon Khan (72) and Damien McGrane (65). The group finished at minus-5.
Storm birdied the second and fifth holes to get back into the tournament. He drained an 18-footer for birdie at the eighth to get to minus-5, one shot behind Bjorn and Montgomerie.
Bjorn raced back into the mix with a birdie at three and a tap-in birdie at the fifth. He holed a 7-foot birdie putt at the seventh and found himself in the lead.
Montgomerie, the 2000 winner here, also climbed the leaderboard with front-nine birdies. He rolled in an 8-foot birdie putt at the third and kicked in a short birdie putt at the ninth.
Montgomerie moved into the lead with a 15-foot birdie putt at the 10th, then fell victim to an off-course distraction at 12. He heard a cell phone during his drive and missed the fairway well right. Montgomerie could not get it out of the rough and walked off with a bogey to lose sole possession of first place.
Meanwhile, Storm cruised to 7-under par thanks to back-to-back birdies at 13 and 14. Montgomerie joined him at minus-7 with a 4-foot birdie putt at the 14th. Bjorn could do no better than pars after his final birdie at seven.
Montgomerie was the first to fall off the pace. At the par-4 15th, the Scotsman missed a 4-foot par putt to give Storm the lead to himself. Montgomerie's approach at 16 sailed over the green and he could not save par to fall two behind Storm.
Bjorn bogeyed the 17th and Storm played 18 with a two-shot cushion. He hit an iron off the tee and had a long second, which he played 45 feet from the hole. Storm lagged his birdie putt to close to 4 feet and holed that putt to save par.
Before Storm's name could be engraved on the trophy, another contender emerged late and that was the overnight leader. Hansen found water at two and double-bogeyed the hole. All totaled, Hansen played the front nine in 3-over 39, but came back on the back side.
He birdied 14 and 16 to find himself one off the lead. Hansen narrowly missed a birdie effort at the 17th and had almost the same length as Storm on 18. Hansen needed a birdie to force a playoff and his putt came up short, giving Storm his first win on tour.
'It's obviously very difficult out there,' said Storm, who got into the British Open with the win. 'The last four are very tricky especially with the wind blowing. It was just make pars and hopefully that would be enough.'
Martin Kaymer (71) and Jyoti Randhawa (68) shared seventh place at 4-under- par 280. Ian Poulter shot a 2-under 69 and took ninth place at 3-under-par 281.
Bradley Dredge (68) and David Lynn (72) tied for 10th at minus-2.