Andrew McLardy, Nolan Henke and Stan Utley were two shots off the pace at 3-under-par 67.
Cheesman got off to a solid start with an impressive front nine, the back side at Crestview Country Club. He began with a birdie at the 10th and added another at the next hole.
At the par-5 14th, Cheesman hit his second shot to 25 feet and drained the putt for an eagle. He continued the assault with a birdie at the par-4 15th and made the turn at minus-5.
Cheesman played steadily under windy conditions until a bogey at the par-4 sixth. The 42-year-old responded with a birdie at the ninth to enter the clubhouse alone atop the leaderboard.
'I just got it going early and kind of hung on there,' said Cheesman, a two-time Buy.Com Tour winner who also played on the PGA Tour. 'The greens here are difficult to read. I struggled a bit in the pro-am trying to figure out which direction the ball was going to go.'
Martin, who finished third at last week's LaSalle Bank Open, had the outright lead at 6-under until two late bogeys dropped him to minus-4.
For Martin, his first top-10 result of 2002 a week ago and his opening-round 68 Thursday have been more than welcome.
'I don't know what it is,' said Martin, whose lone Buy.Com Tour victory came at the 1998 Lakeland Classic. 'I'm not doing anything that drastically different the past two weeks. I'm just keeping it in play and I'm putting well and that helps.'
Martin picked up his first birdie at the third and then ran home a 60-foot putt for birdie at the fifth. He added four birdies over the first six holes on the back nine before the bogeys at 16 and 18.
Zoran Zorkic, who captured the Carolina Classic in May, was part of a large group at 2-under-par 68.
Defending champion Jason Dufner, who has missed the cut in each of his last two starts, struggled with an opening-round 73 to finish eight shots behind Cheesman.
Full-field scores from Wichita Open