Donald's strong finish at the Disney World resort earned him an 8-under 64 and gave him a 2-stroke win at 17-under-par 271 -- his second victory of the season and the fourth of his career.
The $846,000 first-place paycheck enabled Donald to vault over Webb Simpson for the PGA Tour money title in a stunning recovery. The Briton, who entered the final day three shots behind third round co-leaders Justin Leonard and Kevin Chappell, needed to finish in the top two to have a chance at the top spot.
Donald also holds a sizable advantage for the European Tour Order of Merit and could become the first player to win both that honor and the PGA money title in the same year.
Leonard and Chappell, meanwhile, fell off the pace Sunday. Leonard parred the final hole to card a 1-under 71 and take second place at minus-15.
Chappell, meanwhile, stumbled to an even-par 72, sharing third place at 14-under 274 with Sunghoon Kang (68) and Tom Pernice Jr. (69).