SHANGHAI, 15 Nov 2015, (AFP) - The Swede carded a four-under final round of 68 to finish level on 17-under par 271 with American Patrick Reed who shot a 67, forcing the pair to go head-to-head back down the 18th at Lake Malaren.
Reed found the greenside bunker with his second to the long par four while Broberg carved a nine-iron perfectly to the right of the flag and saw it run down a slope to four paces from the hole.
Although Reed splashed out close, the stage was set for the 29-year-old from Stockholm who had won previously three times on the second-tier Challenge Tour but never among the top pros.
He had been faced with an almost identical putt minutes earlier on 18 to win outright but left it short.
This time he made no mistake, firmly rolling the ball down the slope and into the heart of the cup to roars from the packed galleries as he held both arms aloft in triumph.
Broberg was embraced by his caddie and soon after by fellow Swedish tour players Rikard Karlberg and Henrik Stenson who showered him in celebratory champagne.
Fighting back tears, Broberg was almost lost for words after picking up the biggest payday of his career -- $1,166,000 -- and shooting up the Race to Dubai rankings from 61st to 12th.
"That's a dream come true. I've worked so hard all my life for this. I have no words," said the tearful Swede, who started the week ranked 149th in the world but looks certain break the top 100 when the new rankings are released Monday.
"I hit a good swing with my driver, just hit a long one left side," he said off the playoff hole. "Hit a pure nine-iron into the green and made the putt."
He said he would be celebrating later over dinner with his Swedish colleagues on tour including world number seven Stenson, who finished just one shot behind Broberg in a tie for third with An Byeong-Hun of South Korea, Denmark's Lucas Bjerregaard and overnight leader Thongchai Jaidee of Thailand.
"Henrik paid the bill yesterday, so it's my turn today," Broberg laughed.
Reed, who only got into the playoff courtesy of an outrageous eagle two direct from a fairway bunker on the par-four 15th, was able to take the positives away from two weeks in Shanghai where he recorded strong finishes after a tied seventh place in the WGC-HSBC Champions a week ago.
"That's I think five of my last seven events I've finished inside the top 10," said Reed, one of the few Americans to play on both the US PGA and European Tours.
"Just need to keep on plugging along and hopefully close one out shortly."
Rory McIlroy sat out this week but will tee up on Thursday in the DP World Tour Championship, still leading the Race to Dubai by a thread after Danny Willett's tied 28th finish on seven-under was not enough to overtake the Northern Irish world number three.
McIlroy's lead in the standings has been cut to just 1,613 points by the Englishman with 1,333,330 points available to the winner of the season-ending championship next week.
Justin Rose could also have overtaken McIlroy with second place in Shanghai but finished tied seventh.
The English world number six did move to third in the standings, but he is still 650,999 points adrift of McIlroy.
Leading scores after the final round of the BMW Masters at Lake Malaren Golf Club, Shanghai, on Sunday (par 72):
271 - *Kristoffer Broberg (SWE) 69-70-64-68, Patrick Reed (US) 71-69-64-67
*Broberg won on first playoff hole
272 - Henrik Stenson (SWE) 68-71-65-68, Lucas Bjerregaard (DEN) 66-66-70-70, An Byeong-Hun (KOR) 65-71-66-70, Thongchai Jaidee (THA) 67-68-66-71
273 - Justin Rose (ENG) 67-67-72-67, Paul Casey (ENG) 67-69-68-69
274 - Soren Kjeldsen (DEN) 72-67-71-64, Julien Quesne (FRA) 70-69-69-66
275 - Ian Poulter (ENG) 68-68-68-71, Sergio Garcia (ESP) 64-71-67-73
276 - Matthew Fitzpatrick (ENG) 68-71-67-70, Thomas Pieters (BEL) 71-71-63-71, Marcus Fraser (AUS) 70-70-65-71, Ross Fisher (ENG) 66-71-67-72
277 - Andy Sullivan (ENG) 74-71-67-65, David Howell (ENG) 69-71-69-68, Francesco Molinari (ITA) 68-70-69-70, Scott Hend (AUS) 69-73-68-71, Victor Dubuisson (FRA) 65-73-68-71
279 - Branden Grace (RSA 71-71-69-68, Chris Wood (ENG) 70-69-70-70
280 - Graeme Storm (ENG) 72-72-69-67, Emiliano Grillo (ARG) 71-70-74-65, Trevor Fisher Jnr (RSA) 71-71-69-69, Bernd Wiesberger (AUT) 71-69-70-70
281 - Danny Willett (ENG) 72-69-70-70, Alexander Levy (FRA) 73-76-63-69, Peter Uihlein (USA) 71-66-72-72