The 43-year-old Scot, known as “Chippy” all his career, chipped in twice during a brilliant closing 65 and beat Australian Jason Day and Swede Peter Hanson by four.
Less than a year ago the 1999 Open champion was down at 272nd in the rankings. Now he is part of golf’s elite group again.
The victory guarantees him a place in the 64-man Accenture world match play championship in Arizona later this month and the 24-man Volvo World Match Play in Spain in May.
He is on course to win a second Ryder Cup cap 13 years after his first and if he can stay in the top 50 for another seven weeks he will make a return to The Masters at Augusta in April after an eight-year gap.
This was the Aberdeen player’s first success since his long-time coach Adam Hunter died of leukaemia in October and Lawrie was close to tears when reminded of that afterwards.
“I don’t think I can play much better than that,” said Lawrie after finishing with a 15 under par total in an event cut to 54 holes because of Friday’s strong winds.
“I’ve been playing well for a long, long time, but it’s just nice to come out one ahead and shoot seven under.”
It was the joint lowest round of the day and he added: “When you’ve got a chance to win a tournament you don’t sleep as well the night before and things go racing through your mind.
“You’ve got to get back to basics and I did that. I hit some nice shots coming in.”
Also reminded that his 1999 victory in the tournament was followed five months later by lifting the Open Claret Jug at Carnoustie Lawrie said: “Now wouldn’t that be nice to get that again?”
And as for the Ryder Cup he added: “I’ve been trying to keep that to the back of my mind.
“If I keep playing as I am I will get in, there’s no question, but there’s a long way to go and I know as well as anyone that there are a lot of good players.”
The first chip-in was perfectly timed. Lawrie had been caught by Sergio Garcia moments before, but holing out for eagle from just short of the green at the long ninth put him two in front again.
Garcia, six under for the first 11 holes, then bogeyed the 13th and 15th to drop back to joint fifth and instead it was Day who applied the pressure.
The 24-year-old, runner-up in both the Masters and US Open last season, began each half with four successive birdies, but a bogey six on the ninth left him with too much ground to make up. Lawrie went clear with birdies on the 11th, 14th and 16th and victory was effectively sealed when he chipped in again at the short 17th.
Hanson caught Day by pitching in for eagle on the 16th and matching his two-putt birdie on the last. They were round in 67 and 65 respectively.
Fourth was 45-year-old American John Daly. Down at 543rd in the world at the start of the week, it was the former Open champion’s best display since he was second in the 2009 Italian Open.
Lee Westwood and Martin Kaymer, third and fourth on the rankings, finished 12th and ninth respectively, Westwood sharing his position with Jose Maria Olazabal on the Ryder Cup captain’s 46th birthday.