Canadian Brad Fritsch posted a 6-under 66 at Pete Dye Golf Club and is alone in second place, followed by Ron Whittaker, Steve Wheatcroft and Brian Stuard in a tie for third at minus-5.
They are all looking up at Iles, who lost a playoff only two weeks ago at the Knoxville Open.
Iles began on the 10th tee Thursday and quickly went into red figures with a birdie at No. 10. His next birdie came at the par-5 14th, then he closed his opening nine with back-to-back birdies at 17 and 18.
Things didn't go so well on the second nine for Iles. He bogeyed the first hole to fall back to 3 under par for the championship.
That was the final miscue for Iles.
He birdied the third and fourth holes to move into a group tied for the lead at minus-5. Iles birdied the par-5 sixth to keep pace with Fritsch atop the leaderboard.
Iles birdied the par-4 eighth to grab sole possession of the first-round lead. This is a place he believes he should be, thanks to more toughness.
'My coach, my manager, several players all told me I had the shots and I had the talent but I wasn't aggressive enough,' Iles said. 'I didn't have enough mongrel in me.'
Brad Elder, Andrew Johnson, Brendan Steele and Tom Scherrer share sixth place at 4-under 68.
Roger Tambellini, Tjaart van der Walt, Jon Mills, Chris Anderson, Jim Herman, Jin Park, Scott Gardiner, Fabian Gomez, Bob May, Esteban Toledo, Jeff Gove, David Peoples, Jonas Blixt, Jose Teater and John Kimbell are knotted in 10th at minus-3.