'It is a wonderful feeling to have won and especially to do it here in front of so many of my friends and family,' said Schwartzel, who tied for eighth at the Hong Kong Open. 'To get my first win in South Africa is just unbelievable.'
Schwartzel posted a 1-under 71 to join Cheetham, who shot a final-round, 1-over 73 on Sunday, in a tie at 7-under-par 281. The duo headed to the par-5 closing hole at Leopard Creek Country Club for the first sudden-death playoff hole.
Schwartzel's drive stopped in the light rough on the right side, while Cheetham split the fairway with his tee ball. Cheetham's approach landed on the left side of the green, leaving him with a long eagle try. Schwartzel also hit the putting surface, but his ball took the slope on the green and rolled off.
Cheetham left his eagle putt 5 feet short of the hole. The eventual winner chipped his ball five past and the title would come down to a putting contest.
Cheetham's putt missed on the left side, and Schwartzel drained his birdie putt to win the title.
'It was a good chip shot there in the playoff considering I was as nervous as hell,' admitted Schwartzel. 'But shots like that and positions like that are what you practice for, so I am very, very happy.'
Three-time winner and world No. 3 Ernie Els rebounded on Sunday, but came up short of the playoff. He shot a 2-under 70 and tied for second with Warren Abery (70) and Oliver Whiteley (71) at minus-6.
Schwartzel, who trailed by two at the start of the final round, opened with three birdies in his first six holes. He dropped a shot to par, but shared the top spot on the leaderboard with Cheetham.
Cheetham bogeyed the 12th hole to fall one back, but reclaimed his share of the lead with a birdie at the 13th. Schwartzel parred his way around the back nine to keep sole possession of the lead.
Trouble loomed for Cheetham late on the back nine. He bogeyed the 15th, then three-putted from 70 feet for bogey at 16. That dropped him two out of the lead, but Schwartzel let him back into the tournament.
Schwartzel missed a short par putt at the 17th to fall to 7 under par. He had a 12-footer for birdie at the last, but missed, meaning Cheetham or David Frost, needed to only birdie the last to force the playoff.
Frost bogeyed the hole to fall out of contention, but Cheetham reach the par-5 green in two. His lag eagle putt stopped 3 feet from the hole, where he converted the birdie putt to go extra holes.
Frost, who was in search of his first victory since 1999, struggled to a 2-over 74. He tied for sixth place with last year's winner Marcel Siem (67) at 5-under-par 283.
Graeme Storm (68), Damien McGrane (70) and Euan Little (72) shared eighth place at minus-4.