SAN JOSE, October 11, 2013 (AFP) - Overton eagled the par-five ninth hole at CordeValle Golf Club and added five more birdies to take a one-stroke lead over fellow American Brian Harman.
Harman had eight birdies and two bogeys in his six-under 65.
Kyle Stanley finished in third after a five-under 66 highlighted by an eagle at the par-five 15th.
Michael Putnam, who won the money title on the Web.com developmental tour to regain his PGA Tour card, was among a group of six on 67 alongside South Korea's Charlie Wi and J.J. Henry.
Overton, who has been working on a new grip in a bid to ease tendinitis in his wrist, said the move was paying dividends.
"My wrist has been bothering me," he said. "I've had a little tendinitis in it for a few years and (the new grip) allows my wrist to get a little more square at the top of my backswing without having to tweak it a little bit."
Overton parred his first seven holes before a birdie at the eighth, followed by his eagle at the ninth -- where he hit his 250-yard second shot 21 feet from the pin and made the putt.
Back-to-back birdies at 12 and 13 were followed with another brace at 17 and 18 -- tapping in from two feet at the last.
"It would be great if we can continue this thing and keep it rolling," Overton said.
The $5 million tournament was previously part of the USPGA Tour's late season series, a slate of events that in recent years gave rank-and-file pros a chance to earn prize money toward keeping their tour cards as bigger names took a break in the wake of the FedEx Cup playoffs.
This year, the Frys.com Open marks the start of the 2013-2014 season, and like all six events that will be played before January will offer FedEx Cup playoff points and a coveted Masters berth to the winner.
Sweden's Jonas Blixt, who captured his first PGA Tour title here last year, opened his title defence with a two-under 69 that left him in a large group sharing 19th place that also included Fijian veteran Vijay Singh and South African Tyrone Van Aswegen.
Scores on Thursday after the first round of the $5 million USPGA Tour's Frys.com Open (USA unless noted, par 71):
64 - Jeff Overton
65 - Brian Harman
66 - Kyle Stanley
67 - Jason Kokrak, Michael Putnam, J.J. Henry, Charlie Wi (KOR), Jim Herman, Brooks Koepka
68 - Robert Allenby, George McNeill, Alex Aragon, John Peterson, Camilo Villegas (COL), Johnson Wagner, Scott Brown, Justin Hicks, Lee Williams
69 - Luke Guthrie, Jonas Blixt (SWE), Vijay Singh (FIJ), Billy Hurley, Chris Williams, Mark Hubbard, Davis Love, Ben Crane, Jerry Kelly, Will MacKenzie, Tyrone Van Aswegen (RSA), Max Homa, Ryo Ishikawa (JPN), Bud Cauley, Ben Martin