He was one shot better than Geoff Ogilvy.
Donald, who carded a 3-under-par 69 over the final 18 holes, ended at 12-under 276.
"It's nice to finish with a great shot like that," Donald said. "It was a nice way to finish up. It looked pretty good in the air. I had a little mud on the ball, so I was hoping it would fly straight. I had a perfect yardage and it came off beautifully."
Donald earned $990,000 for his victory.
Frank Lickliter (71), Jeff Gove (68), and Stephen Ames (70) all finished at 6-under 282.