Haas, who won the Senior PGA Championship last week, shot 4-under on the back nine and finished at 10-under 203 total, one shot ahead of Andy Bean. Haas also passed Bernhard Langer for first in the points standings with the victory.
Second-round leader Nick Price bogeyed his final hole and finished third with a final-round 69 and 8-under 205 total. Joey Sindelar was fourth at 7-under, and seven players tied for fifth at 6-under 207.
Haas entered the final round two strokes behind Price, but three straight birdies down the stretch gave him the lead for good. He knocked down a 48-foot putt on No. 14, then dropped his tee shot on No. 16 two feet from the pin. A short putt there gave Haas a one-shot lead, and he closed with two straight pars.
Haas in the first player in the eight-year history of the event to win it two straight years.
Price is still searching for his first Champions Tour win. He didnt blow the final-round lead as he did in Austin, Texas, in early May when he shot a 3-over 75, but he missed a number of birdie putts on the back nine.
Price still could have forced a playoff with a birdie on No. 18, but his approach bounced off the green and rolled onto the fringe.
Bean (67) moved up with birdies on Nos. 15 and 16, but he hit his final tee shot into the rough and needed a long putt to finish at 9-under 204.
Tom Purtzer had pulled into a tie for the lead with three holes to go, only to turn in a disastrous finish. His approach on the 17th hole landed in the creek near the green, leading to a bogey that dashed his hopes. A double-bogey on No. 18 gave Purtzer a 6-under 207 total.
Loren Roberts, the runner-up at Glen Oaks two years ago, was at 6-under through 16 holes before he stumbled on Nos. 17 and 18 yet again. Roberts, who blew a final-round lead with two holes to go in 2006, sent a chip past the pin and missed a par putt on No. 17. He then bogeyed the 18th hole and finished the tournament at 6-under 207.