Andrew Pratt and John Merrick, both of whom shared the opening-round lead with Hjertstedt, shot 3-under 69s on Friday. They are tied for second place with Andrew Buckle (68), Gary Christian (67), Scott Petersen (68) and Justin Bolli (66) at minus-9.
Hjertstedt, a two-time winner on the PGA TOUR, but never a champion on the Nationwide Tour, started on the 10th tee Friday and collected his first birdie at the 11th, when he ran home a 12-footer.
He kicked in a short birdie putt at the par-4 14th, but dropped a shot at the par-5 16th. Hjertstedt reclaimed the lost stroke with a 6-foot birdie putt at the par-3 17th.
He made the turn at 2-under 34 and parred his first four holes on his second nine. Hjertstedt missed the green with his second shot at the par-5 fifth, but chipped to 15 feet and converted the birdie putt.
Hjertstedt took advantage of the other par five on his second nine, the 554-yard eight. He reached the green in two with a 5-wood, then two-putted for birdie and sole possession of the lead.
'I just played pretty solid,' acknowledged Hjertstedt, whose best finish this season was a tie for ninth in Tucson on the PGA TOUR. 'It was pretty effortless today. This is the best I've struck the ball in quite a while.'
Hjertstedt is trying to play both tours this season and posted his top finish on the PGA TOUR. It has been almost seven years since his last win (the 1999 Tucson Open), but Hjertstedt believes he is close.
'It's been fun playing golf again,' admitted Hjertstedt. 'It's fun when you work through it because it's easy to give up. There's no easy way back. It's hard work.'
Cliff Kresge, Brendon de Jong and Michael Long all shot rounds of 4-under 68 on Friday. They are knotted in eighth place at 8-under-par 136.
The 36-hole cut came at 2-under-par 142 with 75 players advancing to the weekend.