The defending John Deere Classic champion was tied for first after Round one.
Early in the morning on Thursday, July 11, 2013, Zach Johnson teed off with Steve Stricker and Davis Love III.
Johnson, a Cedar Rapids, Iowa native, completed the first half of the day making six par and three birdies. In the second nine, he made four more birdies.
At seven under par, Johnson and Camilo Villegas held the top spots in the field.
Villegas, from Colombia, made nine birdies in Round one, but also had one bogey.