Atwal, who got to play in the tournament courtesy a Sponsor's Exemption handed out by his friend and practice partner Tiger Woods, ended his campaign with a total of three-over 283.
The Orlando-based golfer, in joint lead after the opening round, was off to an ominous start as he stumbled to a bogey on the first hole.
His poor form continued when he dropped two more strokes on the third and sixth holes to make the turn three-over.
It was a similar story on the back nine as he dropped shots on the 12th and 14th. His only birdie came on the 16th but that was just not enough to change his fortunes.
Atwal, however, did manage to finish ahead of Woods (71), who ended tied 46th at four-over 284.
Englishman Justin Rose (70) picked up the title with a total of 10-under 270. American Ryan Moore (65) finished second at nine-under 271.