PGA Tour veteran Mike Springer and Bob Heintz share second place at 5-under 67. Craig Lile, Tjaart van der Walt, Paul Claxton, Dicky Pride, Mike Standly and Chris Downes are tied for fourth at minus-4.
Johnson mixed two birdies and two bogeys over his first five holes and those two bogeys were the last blemishes on his scorecard. He birdied the sixth hole, then eagled No. 8 to make the turn at 3-under.
Johnson, recently married in February, collected birdies at 10 and 13, then birdied the final two holes to take the first-round lead in his first tournament of 2003.
'My putting, without a doubt, was the key for me today,' said Johnson, who needed only 25 putts on Thursday. 'These greens are firm and if you get on the wrong side of a tier you're struggling to two-putt. I knew if I could just get on the greens and give myself some chances I'd be okay. I also hit my driver pretty straight and that helped.'
Johnson has conditional status on the Nationwide Tour but has yet to make it into any field so far this season. He qualified on Monday to get into this event and hopes for better success this season than his rookie year of 2000, when he made only four cuts in 11 starts.
'Looking back I think I got caught up in just trying to make cuts,' he said. 'My game has matured and improved a lot. My fundamentals are better and I'm more consistent now. My goal isn't to make cuts, it's to win.'
Springer, who won the very first Nationwide Tour event at the 1990 Bakersfield Open, recorded five birdies over his opening nine holes, the back nine at Diamante Golf Club. He traded a birdie for a bogey early in his second nine and parred out for his round of 67.
'I'm really aggressive when I play, but the key to success out here is being able to control your driver,' he said. 'I've taken a lot of risks in the past and some of them paid off and some didn't. Much of it depends on how your day is going for you. Today, I hit seven fairways so I know I've got to hit my driver better if I want to contend on Sunday. I've played long enough to know nobody gets paid on the first day.'
Heintz birdied four of his last seven holes to grab his share of second place. Heintz played the PGA Tour last season but made only six cuts in 28 starts.
Casey Martin shot an opening-round, even-par 72 on Thursday.