Schwartzel, who began the final round at Augusta National four strokes off the pace, showed nerves of steel as he rolled in a 20-footer on the 18th green to complete a six-under-par 66, the lowest score of the day.
The 26-year-old threw both arms skywards in jubilation after his ball dropped into the cup to give him a 14-under total of 274 in the season's opening major. Schwartzel, who launched his round with a sizzling birdie-par-eagle run, became the third South African to win the Masters, following Gary Player (1961, 1974 and 1978) and Trevor Immelman (2008).
“Walking up 18 was such a special feeling,” Schwartzel told reporters after claiming his first US PGA Tour title in only his second Masters appearance.
“I only had a one-shot lead, so you don't want to get too excited about it. You've still got to win the golf tournament. But it just really felt good.”
Adam Scott (67) and Jason Day (68), each aiming to become the first Australian to triumph at Augusta National, shared second at 12-under after playing together on the final day.
Four-times champion Tiger Woods, seeking his first tournament victory in nearly 17 months, had to settle for a tie for fourth after closing with a 67. Woods finished at 10-under with Australian Geoff Ogilvy (67) and Briton Luke Donald (69).
Overnight leader Rory McIlroy of Britain, four ahead going into the final round, suffered a nightmare day as he tumbled out of contention with an 80 for a four-under total of 284. The 21-year-old Northern Irishman clung to a one-stroke lead after the first nine holes before spiralling downwards.
He triple-bogeyed the 10th after pulling his tee shot in between two Augusta National residential cabins and twice hit trees before reaching the green. McIlroy then bogeyed the 11th, after three-putting, and also the par-three 12th, where he four-putted from 25 feet.
“I'm very disappointed,” the world number nine said. “I was leading this golf tournament with nine holes to go and I just unravelled. It's going to be hard to take for a few days, but I'll get over it.”
On a sweltering afternoon of breathtaking shot-making at Augusta National, the leaderboard fluctuated repeatedly and eight different players held at least a share of the lead as roars from the fans repeatedly echoed amid the Georgian pines.
Scott appeared to take control on the back nine with birdies at the 11th and 14th, where he coolly knocked in a seven-footer to get to 11-under. A tap-in birdie at the par-three 16th kept him one ahead.
Schwartzel, however, emerged from the logjam with his stunning finish.
He very nearly chipped in for eagle from behind the green at the par-five 15th, where he knocked in a four-footer for birdie, and then sank further putts from 18 and 12 feet at the 16th and 17th.
In perfect position off the tee at the par-four 18th where he led by one, he struck his approach to 20 feet before again finding the middle of the cup with his birdie putt.
Leading scores (after 72 holes): 274: Charl Schwartzel (SA, 69, 71, 68, 66); 276: Jason Day (Aus, 72, 64, 72, 68), Adam Scott (72, 70, 67, 67); 278: Luke Donald (Bri, 68, 69, 69), Geoff Ogilvy (US, 69, 69, 73, 67), Tiger Woods (US, 71, 66, 74, 67).
