Wallace birdied five of his last six holes in a 67 to get to 19 under alongside fellow Englishmen Steven Brown, Jonathan Thomson and Lee Westwood before birdies on both extra holes handed him a fourth European Tour win at Silkeborg Ry Golf Club.
Brown and Wallace both put their approaches inside six feet on the first play-off hole for a pair of birdies before Wallace went even closer on the next with Brown only able to make a par.
Wallace moves to 17th in the Race to Dubai Rankings presented by Rolex and will break into the top 60 of the Official World Golf Ranking for the first time in his career.