The Australian managed a three-under 68 on a tough day for scoring to lead by two on Thursday.
Playing in the morning on the Robert Trent Jones Jr.-designed course with deep, thick rough, Pampling had seven birdies, a double bogey near the end of his round and two bogeys.
"The rough kind of lays back into you, so you really can't get the club on the ball." Pampling said. "It's quite difficult to judge. Hopefully, won't be doing that too many times.
"It was obviously a fun day. I'd been playing well for the last month or so. To get here and see the course, it felt good. I drove it really well and made a lot of birdies out there.
"Just the one hole made a little mistake on, tried to get a little too aggressive. On the whole, I putted it really well, which was nice to see the balls going in. It's nice to get a good view of the greens and can pick the breaks early on."
The 53-year-old Queenslander has one Champions victory - the 2021 Boeing Classic - after winning three times on the PGA Tour.
He is being pursued by some of the game's biggest names, including Retief Goosen and Miguel Angel Jimenez who both had 70.
Two-time US Open champion Goosen got right to the point after his round.
"You got to hit the fairways, otherwise, you've got no shot," said the 54-year-old South African who won the US Open in 2001 and 2004.
He had five birdies and four bogeys in his afternoon round.
"The rough here is like a normal US Open," he said. "The three lies I had, there was no chance I'd even get near the green.
"Even on No.8, I was 90 yards from the front edge. I hit a sand wedge as hard as I could, and it probably carried 40."
Jimenez and University of Illinois golf coach Mike Small matched Goosen at 70.
"It's fair. It's good," Jimenez said. "The ball is nice, they are holding good and fairways also holding well. It's a very good test."
Bernhard Langer, the 65-year-old Champions career victory leader, was at 71 with Australian Richard Green, Ernie Els, David Toms, Jerry Kelly, Jeff Maggert, Bob Sowards, James Kingston, Adilson da Silva and Ken Tanigawa.
Langer stayed out of the rough.
"Thank goodness I wasn't in it," Langer said. "I can't talk much about it, but I tried to hit a few shots in the practice rounds and it's very punishing."
Defending champion Padraig Harrington opened with a 74. Coming off a victory Sunday in the Champions event in New York, the Irishman had three birdies, a double bogey and four bogeys.
"Doesn't your mother always tell you you're going to have days like this, really a struggle to focus," said Harrington.
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