Leishman, who is looking for his first Nationwide Tour title, completed 36 holes at 11-under-par 133.
First-round co-leaders Tom Gillis and Spencer Levin both carded 2-under 70s in the second round. They dropped into a share of second at minus-8, where they were joined by Michael Boyd (67) and Brendon Todd (68).
Reid Edstrom, who shared the first-round lead with Gillis and Levin, stumbled to a 3-over 75 that dropped him into a tie for 15th at minus-3.
Leishman played the back nine first and opened with a birdie on the 10th. He parred four in a row from the 11th before making birdie on the par-5 15th at Midland Country Club.
After a birdie on the 18th, Leishman headed to the front nine at minus-8.
Leishman birdied the two par 5s on the front nine, Nos. 2 and 4, to climb to 10 under. He parred four straight from the fifth before closing with a birdie at the ninth, his last, to lead by three after two rounds.
'Today the greens were softer and there's nowhere near as much wind, but yesterday was brutal,' said Leishman, who held the 36-hole lead at the Utah Championship as well. 'I'll draw on my experience from Utah over the weekend. I learned a lot from that.'
Gillis carded three birdies on the front nine and a lone bogey on the back to share second at minus-8.
Levin drained three consecutive birdies from the 14th. He gave two strokes back with a double-bogey on the par-five second. Levin got one shot back with a birdie on the fourth before parring out.
Boyd was 5 under through 12 holes with three birdies and an eagle. After a bogey at 13, he bounced back with a birdie at 14. Boyd traded a bogey for a birdie from the 17th to post his 67.
Todd carded two bogeys and two birdies on the back nine, his first nine holes. On the front nine, he birdied three in a row from the second, then birdied the seventh to get to minus-8.
Michael Putnam (67) and Ricky Barnes (68), who stands 25th on the money list, are tied for sixth at 7-under-par 137.
The cut line fell at even-par 144 with 69 players moving on to the weekend.
With the top 25 on the money list earning their PGA Tour card for next season, several players battling for their cards missed the cut. They included Matt Every, Ewan Porter, Bryan DeCorso and Chris Anderson.