Masters champion Garcia, who won the last staging of the event in 2011, carded a closing 67 to finish 12 under par, a shot ahead of Holland’s Joost Luiten, who shot 66.
England’s Daniel Brooks was four strokes back in third, a result good enough to secure his European Tour card for next season by moving him from 123rd on the Race to Dubai to inside the top 100.
And Welshman Jamie Donaldson, who secured the winning point in the 2014 Ryder Cup, also climbed from 118th to 99th on the money list thanks to claiming fourth place — his best result of the season — on five under.
“It was amazing,” Garcia said after closing the gap on Race to Dubai leader Tommy Fleetwood to under 800,000 points. “Daniel played great with everything he had on the line, trying to keep his card, and Joost played unbelievable. I played really well and felt maybe I could get away and he kept coming back and made it an amazing match.”
After seeing his one-shot overnight lead wiped out when Brooks birdied the second, Garcia responded with a birdie on the par-five fourth and ended the front nine in style by using a fairway wood to hole from the fringe for a birdie on nine.
Watched by his wife Angela and father Victor, Garcia then holed from 10 feet for birdie on the 10th and three feet on the next to move three clear, only to bogey the 12th. The gap was down to one when Luiten birdied the 13th and another birdie on the 15th drew the Dutchman level, only for the five-time European Tour winner to three-putt the next.
Both men birdied the par-five 17th and when Luiten’s birdie attempt on the last caught the edge of the hole and stayed out, Garcia — who was awarded honorary life membership of the European Tour on Saturday — had the luxury of two-putting from close range to claim a third win of the season.
Meanwhile Welshman Stephen Dodd won his second European Senior Tour title on a dramatic final day at the European Senior Masters, securing victory with a 40-foot birdie at 18 at Forest of Arden.
Dodd started the day level par, three behind 36-hole leader Clark Dennis but made ground as he went out in 34 strokes, two under par. The 51-year-old spent most of the day chasing both Dennis and 2014 Ryder Cup captain Paul McGinley. Playing in the penultimate group, Dodd found the fringe at the front of the green on the par three 18th. The Welshman made the putt, which rolled around the hole before dropping in, to join McGinley at the top of the leaderboard on two under par.
McGinley, playing his fourth Senior Tour event, struck his tee shot short of the green and missed a tricky putt for par to drop to one under. Dennis found the green, but missed a birdie putt which would have forced a play-off, handing Dodd his second title.