Fox completed his final 13 holes in eight under par to finish with a 67 and win the competition.
Ryan Fox of New Zealand defeated rising sensation Ludvig Aberg in the final round to win the BMW PGA Championship at Wentworth on Sunday.
Following a triple-bogey seven on the third hole, Fox appeared to be eliminated from contention. Fox had started the day three strokes behind overnight leader Aberg.
However, the 36-year-old completed his final 13 holes in eight under par to finish with a score of 67.
Fox defeated Tyrrell Hatton and Aaron Rai by one stroke thanks to his 18-under par final score.
Rai missed a long eagle putt on the 18th that would have at the very least forced a play-off and handed him the victory.
The third-ranked golfer in the world, Jon Rahm, shot a 68 to finish in fourth place on 16 under after finishing second in each of his previous two Wentworth tournaments.
The top 10 was filled with seven Ryder Cup players from Europe, with Rory McIlroy breaking through the field with a round of 65.
In just his 10th professional event, Sweden's Aberg, who was going for consecutive tournament triumphs, had a two-shot lead after 54 holes.
However, the 23-year-old phenom struggled in the final three holes, finishing with a final score of 76, including two double bogeys.
Fox started strong, making four birdies in five holes starting at the tenth.
He was lucky that his errant drive on the 15th hole did not go deep into the trees because he blasted an excellent second shot to 10 feet and made the birdie putt to take the lead by a comfortable margin.
Fox calmly holed from six feet to secure a fourth DP World Tour championship when Rai's eagle effort hit the edge of the green and stayed out after Hatton birdied the last to create the possibility of a play-off.