Haas sank a 2-foot par putt on the final hole for a 4-over-par-74 and a total of 7-under 287, the highest winning score in the tournament's history.
Langer, who led going into the last round, slipped to a 76 and an 8-over 288.
"I'm very glad it's over," said Haas, who had just one birdie, at the par 4 fifth hole.
The victory, which earned Haas $360,000, was his 11th on the Champions Tour.
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