The 43-year-old Swede is currently languishing in 179th spot in the Race to Dubai and needs to win the tournament to climb into the top 110 and avoid going back to Qualifying School.
Hedblom, who has three tour wins, carded a four-under-par 68 to form part of a four-man group at the top of the leaderboard with South Korea's Jin Jeong and Australian duo James Nitties and Clint Rice.
"It was an interesting day. The game didn't feel that good, but I kept the ball in the fairways," Hedblom told reporters after mixing six birdies with two bogeys at the Lake Karrinyup Country Club.
"I hit a few bad ones and I was lucky to bounce in the fairway, stuff like that. But a solid start."
Hedblom missed seven of his first eight cuts this year but promised to give his all to retain his playing rights.
"I'm so far back. I need a win or to finish second really," said. "Well, I mean, you have nothing to hold back. You just have to go for everything.
"You're not happy to finish third or fourth or fifth or sixth or 10th. Just play as good as you can. The game is there, you just need a little bit of confidence."
American Ryder Cup team member Dustin Johnson hit six birdies to offset three bogeys and was a shot behind the leading quartet in a share of the fifth at the $2 million (£1.24 million) event co-sanctioned by the PGA Tour of Australia.
"I played pretty well. Missed a couple short putts, but other than that, I hit it pretty well," Johnson said.
"The greens are really tricky. They are really firm and they are really fast. You've really got to be careful where you hit the ball on your second shots.
"You don't want too many downhill putts because it's hard to stop the ball. If you miss the green in the wrong side, you're dead."
Defending champion Bo Van Pelt of the US was a shot further back in a tie for 13th spot after carding a two-under-par 70.