The South African finished on 273, 15 under par, to win his third PGA title in his native country with his compatriot Richard Kaplan second, four shots back.
England's Steve Webster shared third place on 280 with three others after shooting a 70. South African David Frost, with a closing 66, Jeev Milkha Singh of India (70) and the Australian Stephen Leaney (69) were equal third.
Now Els, who hopes to add another major this year to his two US Open titles, is determined to climb the rankings and win back the top spot from the American Tiger Woods.
"I can catch Tiger Woods and the others. I know I have the talent to do it and get the No 1 spot back," said Els, currently the world No 5.
Els admitted that he had trouble on the greens. "But I did what I had to do," he said. "I hit the fairways and hit the greens. I gave myself birdie chances but the putts wouldn't drop.
"I played more solid than I have since before the last US Open and I'm just itching to get back on the US tour and take on the big boys."
The South African claimed he was happy with his swing after working hard on it, but confessed: "Now I must start working on my putting."
Els, who took a congratulatory phone call from President Nelson Mandela on the 18th green after being awarded his prize, won with the same 15- under-par total that took him to victory in the 1992 South African Open. He also shot the same total when finishing second last year.
He stood at the back of the 18th green at Houghton Golf Club with the Alfred Dunhill PGA trophy in one hand and a cellphone in the other. President Nelson Mandela was on the line, and Els was speechless.
"I just listened," Els recounted of the call. "What do you say to a great man like that? He congratulated me. I haven't spoken to him for two years, so it was nice. He also wished me well for my golf and my marriage."
Els, who also won the title in 1992 and 1995 "It's nice to be in the winner's circle again. I haven't been in this position for a while."
"I must get to a roulette table and try my luck on number 15 the first chance I get," he joked.
Webster, the former English Amateur champion, who held third place on his own for most of the day, could not pick up a birdie after the 11th and saw three players catch him up.
"My finish was disappointing but it was a great start to the year," he said.
England's Peter Baker finished ninth on six under after a final round 70.
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