Leonard Thompson, Larry Nelson and Vicente Fernandez each shot final round 66s to share second place at 13-under-par 197.
Gilder, who held a share of the lead entering the final round, predicted Saturday what was to come on.
'You're going to have to go low again. I might need to shoot 7-under to win,' he said after his round Saturday.
Gilder came out of the gates on fire. He birdied the first three holes to get to 13-under and built on his lead with a birdie at the par-5 seventh.
On the back nine, Gilder again rolled in three straight birdies from the 11th. He stumbled with a bogey at the par-4 14th but it would not matter. He erased that mistake with a birdie at the 15th to secure the win.
Tom Watson, who shared the lead with Gilder after two rounds, could only manage a 4-over round of 74 to fall into a tie for 15th. He is now 0-for-85 lifetime in the state of Florida covering his time on the PGA and Champions Tours.