Coltart rallied from early trouble with three late birdies over his final eight holes at De Vere Slaley Hall to shoot an even-par round of 72 and win the event by a stroke at 11-under 277.
Andrew Coltart on his win
Obviously, I feel pretty pleased, said Coltart after his round. It was kind of nerve-wracking and at times it wasnt pretty out there at all, but I managed to grind it out and come through.
Stephen Gallacher (68) and Englands Paul Casey (69) finished in joint second at 10-under, while Bradley Dredge (72) stumbled down the stretch to finish tied with two others at minus-nine.
For the recently-turned 31-year-old Coltart, the victory marks his second win in nine years on the tour, his first coming at the 1998 Qatar Masters.
Following the round, however, he was quite aware that he received a fair amount of help from Welshman Bradley Dredge.
Dredge, playing in the penultimate group and tied with Coltart at minus-11 entering the finishing hole, pulled his drive into the left rough and was not able to reach the green with his second shot.
His third was pitched a bit too hard and went through the green. From there, he required three strokes to get in the hole, making a double-bogey six and falling two back at 9-under.
At that point, all that was left for Coltart ' who had been watching the debacle from the 18th fairway ' was a standard par.
He delivered, playing the hole in textbook fashion, recording a four and gaining the outright victory.
Im proud of the way I handled myself and hopefully this is the springboard to future successes for me, Coltart stated.
To be certain, it has been good for his Ryder Cup standings. Coltarts winning purse of 217,209 euro moved him into the tenth spot on the Volvo Order of Merit list.
A couple more good showings by September's big event, and he should be in good position for making the team.
If he does, it will mark his second Ryder Cup appearance in a row. In 1999, he was selected as a controversial captains pick by Mark James.
His only appearance in that edition came in the singles matches, where he was paired against Tiger Woods and lost 3-and-2. Europe would ultimately lose by one point.
Full-field scores from the Great North Open