The long-hitting American fired a flawless six-under-par 64 on the tight, tree-lined layout at Waialae Country Club in Honolulu to finish level with South African Tim Clark, two strokes behind pacesetting rookie Scott Langley.
Russell Henley, like fellow American Langley launching his maiden season on the US circuit, started out with an eight-birdie 63 to trail by just one after a breezy, mainly overcast, day.
Piercy, who tied for 13th at the US PGA Tour's windswept season-opening Tournament of Champions at Kapalua on Tuesday, was delighted with his improved putting at Waialae.
"I struck the ball well last week but I didn't feel like I rolled the ball well putting," the 34-year-old American said after recording three birdies either side of the turn.
"I made a couple of little changes and I rolled it better today.
"The wind wasn't even blowing today compared to last week," said Piercy, referring to the continual gusts of over 40mph (64.4 kph) which prevented play over the first three scheduled days at Kapalua.
"I just played solid today, hit it in a lot of fairways, hit a lot of greens, made two fairly key putts and took care of the par fives."
Piercy, who won his second US PGA Tour title at last year's Canadian Open, has set his sights on at least doubling his career tally of wins on the US circuit by the end of 2013.
"You always want to win and for it to be a good year, I think I have to win more than once," he said. "Obviously a Major is a goal.
"When you're first out here you feel like you're always on the defensive so you don't lose your (tour) card, where now I feel like I can be aggressive to see how good I really can be."
Langley, who earned his 2013 US PGA Tour card after finishing joint 17th at the qualifying school, was still pinching himself after compiling a superb round that included six birdies and an eagle at the ninth.
"To go bogey-free my first event as a full member of the Tour ... wow!" the 23-year-old smiled. "I was pretty nervous starting out, and kind of settled down after three or four holes.
"I made some nice birdies early, and that kind of got me in a nice rhythm for the day.
"Russell and I were walking up the 16th fairway ... you could see the ocean behind, PGA Tour signs everywhere. We looked at each other and realised this is pretty cool."
Dustin Johnson, who powered to victory by three shots at the Tournament of Champions on Tuesday, bogeyed his last two holes to open with a 70 while US Open champion Webb Simpson carded a 66.
Fellow American Johnson Wagner launched his title defence with a four-bogey 71 in the US PGA Tour's first full-field event of the season.
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