But it was Robert Gamez who got out of the gates quickly by shooting a front-nine 30, then coasted in with a back side 33 to finish at 7-under par, one stroke ahead of John Huston and Frank Lickliter.
Gamez, who hasn't finished in the top 40 in his last six tour events, birdied his first two holes on the day, then strung together three in a row at his sixth, seventh and eighth holes. A bogey at his fifth kept him from an opening 29.
'I played solid all day,' said Gamez. 'I hit a lot of good golf shots and I started out well. That's what you have to do to shoot a good score.'
Huston enjoyed a bogey-free 6-under 64 with three birdies apiece on both the front and back. He comes in with a fourth and tie for 13th in his last two starts.
'It is good to get off to a good start,' said Huston. 'I played pretty well. I hit probably pretty much every fairway and I think I only missed one green. I didn't make a lot of long putts, but I made most of the ones that I should have made.'
Lickliter had a lone bogey at the seventh but otherwise had a flawless day, shooting 32-32 to grab a share of second place.
D.A. Weibring is alone in fourth after a bogey-free 65 that saw him carding three birdies on the inward nine.
A group of four players are just three back of the lead at 4-under, including Texas native Mark Brooks.
Senior Tour player Tom Kite, 52, finds himself on the leader board after a wild day on the links. Four bogeys against three birdies had him 1-over on the front nine, but four birdies on the back got him to 3-under on the day.
Defending champion Leonard struggled home with three birdies and two bogeys in a 1-under-par 69.
PGA champion Rich Beem also finish at 1-under 69 despite stumbling out of the blocks with bogeys on his first two holes.
Full-field scores from the Valero Texas Open