Moore -- a Las Vegas resident and alumnus of the University of Nevada-Las Vegas -- logged three birdies on the back nine at the TPC Summerlin course in Las Vegas, enabling him to edge Brendon de Jonge by one shot.
Moore, in winning his second PGA Tour event, bested the previous mark of 261 set last year by Kevin Na.
Third round co-leader de Jonge settled for a 4-under 67, claiming second place at minus-23.
Jonas Blixt, who also held a share of the lead after 54 holes, managed a 70 Sunday to grab sole possession of third at 20-under 264.
Jason Day (65) was fourth at minus-18 and Bill Lunde (66) claimed fifth at minus-15.