"You have nothing to hold back. You have to go for everything," the 43-year-old Swede said after a round containing six birdies and two bogeys. "The game didn't feel that good, but I kept the ball in the fairways.
"I hit a few bad ones and I was lucky to bounce in the fairway. But a solid start."
Hedblom, Jeong and Australians James Nitties and Clint Rice have a one-stroke buffer over a group of eight players including Dustin Johnson, European Tour players Sam Little and Bjorn Akesson and Australia's Nick O'Hern.
Defending champion Bo van Pelt was a stroke further behind.
"It's a golf course where you need to shoot 3 or 4 under each day. Then maybe have a good day where you shoot 6 or 7 under," Johnson said of the Lake Karrinyup Country Club setup. "I think I've got a pretty good game plan for the golf course."
The highlight of Jeong's round was an eagle at the 406-meter, par-4 18th
-- his ninth hole.
"I hit 6-iron from 167 meters -- I didn't think it was going to be in but I hit a pretty good shot ... heard people cheering," Jeong said. "If I play well like today, I can be top of the leaderboard as well."