The Welshman produced eight birdies in his final round to fend off challengers Anthony Wall, Rafa Cabrera-Bello, Fabrizio Zanotti and Mikael Lundberg, winning emphatically by four shots, to delight the 112,280 spectators who flocked to Northern Ireland.
While most players would have afforded themselves a glance at the leaderboard throughout the afternoon, Donaldson, who led after three rounds but started his round behind Lundberg, admitted he kept away from how things were transpiring around him.
“I didn't really look at any leaderboards on the way around,” he said. “I didn't really know what was going on.”
It seemed this title was destined for the 36 year old back on Thursday when he claimed his first European Tour ace.
“To have a hole in one the first time in a tournament, and to win it, as well, is very special,” he added.
He ended his five-year association with caddie Jamie Baker but paid tribute to his role in ending his long wait for European Tour success.
“He's a great mate and he did great for me for four or five years,” Donaldson said. "He's a good mate of mine and I think he'll just be happy obviously to see me win, really.“
Wall, who along with Cabrera-Bello and Zanotti, finished four shots adrift of Donaldson, paid tribute to his playing partner on the final round.
“I've never doubted him. He's a class act and a super, super player, and he deserves everything he gets because he does work hard and he's got loads of talent,” said the Englishman who was always facing an uphill task after a triple bogey eight on the second.
Lundberg turned in 29 to wrestle the lead from Donaldson early on only for the Welshman to rally with successive birdies at the second, third and fourth.
He dropped shots at the 11th and 16th, but squeezed four birdies into the back nine to remain at the leaderboard’s summit.Cabrera-Bello’s hopes of adding this tournament to his Omega Dubai Desert Classic crown earlier this year were going well until an error out of the rough on the 17th proved costly.
Zanotti produced the most consistent round, recording half a dozen birdies and 12 pars in his six under.
David Drysdale, Graeme McDowell and Ross Fisher, who had two eagles on the front nine, also carded 66.
But, with those players back in the clubhouse, Donaldson remained undeterred at the end with a marvellous second shot on the par five 17th setting him up for another birdie.
He held a two shot lead over Wall going into the last and was able to lap up the applause once his drive had found the fairway from the tee.
He finished in style by rolling in his birdie putt to finish with 66, the best of his four rounds.
The crowd, who sold out the venue for four straight days, were perhaps hoping for a local success but McDowell, Rory McIlroy and Padraig Harrington were unable to provide the fairytale finish for the viewing masses.
Nevertheless, the players were unanimous in their praise for the spectators with fellow Northern Irishman Michael Hoey, saying: "All of the players are saying this is by far the best tournament they have been to crowd-wise.”