Gillis, who began the day with a one-shot lead, stretched his advantage to five shots midway through the round at the Pete Dye Golf Club.
The lead dropped to two after a double-bogey, but Gillis steadied himself down the stretch with four closing pars to keep Cameron Percy (68) and Roger Tambellini (68) at bay.
Gillis finished at 15-under 273 and collected $108,000, vaulting him from No. 108 to No. 10 on the money list
This gives me a start to what I want to do and thats being in the top-25 and graduate back to the PGA Tour, said Gillis, who played on Tour in 2003 and 2005. I wish we were done right now.
The victory was the first of the season for Gillis.
I felt like Ive been playing pretty good for the last two months, he said. I just kept reminding myself to keep my head on, stay calm and let it come to me.