The big-hitting Belgian hit the front on the first and never looked back, opening up a three-shot lead just before the turn at Yas Links and holding off the challenge of a high-class chasing pack on the way home.
Rolex Series winner Rafa Cabrera Bello briefly caught him on the back nine but as those around him stumbled, Pieters kept his cool to finish at ten under, one clear of Spaniard Cabrera Bello and India's Shubhankar Sharma and two ahead of Frenchman Victor Dubuisson and Norwegian Viktor Hovland.
Defending champion Tyrrell Hatton was then at seven under alongside fellow Englishmen James Morrison and Ian Poulter and Dane Jeff Winther, with Scotsman Scott Jamieson and Major Champion Adam Scott a further shot back.
Pieters becomes the first Belgian to win a Rolex Series event and claims his sixth DP World Tour title just 77 days after he won his fifth at the Portugal Masters.
The victory also sends him back into the top 50 on the Official World Golf Ranking - potentially as high as 31st - and straight to the top of the fledgling DP World Tour Rankings in Partnership with Rolex.
"Winning a Rolex Series, it's as good as it gets in Europe," he said. "Hopefully this lists me, I'm not sure where, but I want to play all of the big tournaments and hopefully this gets me close.
"Top-50 is your strive point and when I jumped out maybe three years ago, I took it badly, but I'm happy to be back again.
"I feel like I've turned the corner and I'm playing really good golf. I'm really in control of my ball flight and it's nice to feel like that and making putts as well. My putting has improved massively and I felt like that's the thing that really kept me going on the weekend.
He added: "I just hope all the juniors back at home are watching this. I used to watch as a kid and think it was impossible for me but then Nico (Colsaerts) came on the scene and started winning. It's stuff like that that inspires kids and hopefully I can do that back home."
Overnight leader Jamieson surrendered his advantage on the first as he failed to get up and down from a tough position in the sand and when he missed the green again on the second, Pieters led alone after two opening pars.
Winning a Rolex Series, it's as good as it gets in Europe
Another missed green and another failure to get up and down then dropped Jamieson two back and Pieters maintained that lead until he put a wonderful tee-shot to six feet at the eighth and moved three ahead.
Cabrera Bello had holed a 27-footer on the third but gave the shot back on the fourth before he made a two-putt birdie on the par-five seventh, with an approach to six feet at the ninth seeing him turn in 34 and trim the lead to two.
Pieters missed a good birdie chance at the tenth and when he did the same at the next and ended up with a three-putt, his advantage was down to one.
Cabrera Bello then found rough off the tee at the 14th but played an excellent recovery and holed from seven feet to join the lead.
Sharma had sandwiched a double-bogey after a poor tee-shot on the third with a birdie on the par-five second and a 30-footer on the fifth before three-putting the eighth to turn in 37.
He holed from 28 and 30 feet on the tenth and 14th to get to nine under and a par on the 15th proved to be a good result as playing-partner Cabrera Bello failed to get up and down to put Pieters back in the lead.
Cabrera Bello dropped another shot on the 16th after being lucky not to find the water with his second and Sharma's failure to get up and down from the sand at the 17th gave Pieters a two-shot cushion.
The second-placed duo both claimed birdies on the par-five last but in the group behind Pieters decided to lay up and made a routine par for victory.
Cabrera Bello carded a 70, one shot fewer than Sharma, while Dubuisson signed for a 69 and Hovland finished with a 72.
Hovland recovered from a triple-bogey on the third to get within one of the lead but a double on the 15th scuppered his chances, while Dubuisson made four birdies and a single bogey.