The 33-year-old South African became the first player since Steve Jones in 1989 to win the first two tournaments of the season by capturing the Sony Open Sunday in Honolulu, Hawaii.
Els shot 3-under 67 at the Waialae Country Club to match Aaron Baddeley, who had a 69, at 16-under-par 264.
He then made an improbable 43-foot birdie from the fringe on the second extra hole. Baddeley had a 20-footer to continue the playoff, but left it inches short.
'It was a fun day,' said Els, who earned his 12th tour win. 'I thought the kid was gonna go away, but he kept at me. Unlucky for Aaron, but he's going to win a lot of titles.'
Els added another $810,000 to his bank account. He collected $1 million in his record-breaking performance a week ago in Maui. He won the Mercedes Championships - by eight shots - in 31-under par, a tour record in relation to par.
This win was a bit harder to come by.
Baddeley, making his first start as a card-carrying member of the PGA Tour, had his worst ball-striking round of the week ' he hit four of 14 fairways and nine of 18 greens in regulation, but still managed to hang with the second-ranked player in the world.
Both men made four-foot birdie putts on the first extra hole, the par-5 18th. They then went back to the 353-yard, par-4 10th.
Els had driven the hole earlier in the day, but hooked his tee shot into the rough the second time around. Baddeleys tee shot finished in the front left greenside bunker.
With little green to work with, and a tree limb impeding a flop shot, Els ran his pitch shot through the green, 43 feet from the hole.
Baddeley had a straight-forward - albeit lengthy - bunker shot, but blasted out well short of the hole. After Els ran his birdie bomb home, and then Baddeleys putt to tie died on the lip.
'I didn't strike it the best today but I was there and had a chance to win in the end,' said Baddeley. 'Ernie didn't make many mistakes. He was putting the pressure on me to drive it in the fairway as well or hit it on the green. That and he was very composed.'
The victory was a bit of redemption for Els. He lost to Tiger Woods in a playoff in the 2000 Mercedes Championships, when Woods made a 40-foot birdie on the second extra hole to prevail.
'Tiger made that putt on me and I had a chance to tie him and I left it on the edge,' said Els. 'The world keeps on turning. Sometimes it works out for you.'
Els started this Sunday two back of Baddeley, but took a one-shot lead into the last after a bizarre 17th hole.
Els' 25-foot birdie putt was tracking toward the cup when it hit Baddeley's marker to keep it from going in.
Baddeley was ready to strike his three-foot par putt when he backed off after hearing a portable toliet door close. He re-started his routine, but lipped out the putt.
Last year, John Cook was distracted by a ringing cell phone at 17 and hit his tee shot in a greenside bunker. He bogeyed the hole and ended up one stroke behind eventual winner Jerry Kelly.
Baddeley was given a reprieve, however, when Els left his 15-foot birdie putt for victory at 18 short of the hole. Baddeley then converted one from nearly the same length to force the extra session.
Chris DiMarco shot 4-under 66 to finish third, two back of Els and Baddeley. Defending champion Kelly (65) eagled the last to tie Robert Allenby (66) for fourth place, at 12-under.