Kuchar birdied his first three holes on his way to a second straight seven-under-par 63 at Waialae Country Club in Honolulu.
He posted a 14-under 126 halfway total, one stroke better than fellow American Andrew Putnam, who shot a bogey-free 65.
Canadian first round leader Adam Svensson plunged back to reality with a 74 that was 13 strokes higher than his Thursday effort.
He at least made the cut, more than could be said for Jordan Spieth, who missed by a stroke despite a 66 for one-under.
The three-times major champion, speaking to himself constantly as per usual, gave himself a chance of qualifying for the weekend when he birdied the 15th and 16th, but a missed 10-footer at the penultimate hole cost him dearly.
Leader Kuchar has enjoyed a new lease of life in the early part off the 2018-19 season.
Overlooked for last year's U.S. Ryder Cup team after an inconsistent summer, he hit the ground running in the new season and a win at the Mayakoba Classic in November, the eighth of his career, ended a five-year victory drought.
"I found some good stuff between seasons ... and then things really heated up in Mexico," he said.
"I feel awfully in control of what I'm doing."
The world number 32 said the quality of his play had been a little better on Thursday, even if his scores had been the same.
"Yesterday was a little cleaner, found more fairways. Today (I hit) a couple of balls in the rough."
Second-placed Putnam birdied his final hole, the par-five ninth, thanks to a deft 30-yard pitch over a bunker and down to inside three feet.
Putnam hardly had an ideal tournament preparation after a bee sting to his foot on Tuesday prevented him from playing in the Wednesday pro-am.
"It was pretty tough to walk but obviously things worked out pretty well," he said.
(Reporting by Andrew Both in Cary, North Carolina; editing by Amlan Chakraborty)