The former world junior champion completed 14 holes of his second round in 5-under at the Kuala Lumpur Golf and Country Club to lead the $2 million event on 9-under.
A shot behind was Spaniard Alejandro Canizares, who finished his round in 69 for a total of 8-under 136. Angelo Que of the Philippines and Denmark's Soren Hansen were a further stroke back on 137 after returning 67s in the morning session.
A lightning storm stopped play for two hours and 20 minutes in the afternoon, leaving 58 players unable to complete the second round. They will return Saturday morning to finish their remaining holes.
The 20-year-old Kiradech rose to the top of the leaderboard when he holed his third shot from 30 yards out at the par 5 fifth hole.
He said he changed to new clubs before the Asian Tour because he wasn't playing well with the old set. But even the new set didn't feel right and he got yet another set of clubs before coming to this tournament.
Korean star K.J. Choi stayed in the hunt for a second Malaysian title in five months with 7-under for the tournament after playing 16 holes in 2-under, which included an eagle two.
Two-time Malaysian Open winner Thongchai Jaidee of Thailand was a further stroke back where he was even par through 16 holes as well.
Canizares, whose father Jose Maria was a member of Europe's victorious Ryder Cup team on four occasions, is bidding for a second career victory following his lone success at the 2006 Russian Open.
Canizares pulled his second shot into the last and was in the semi-rough, which he decided to putt anyway.
Que started strongly with four consecutive birdies from the third hole but bogeyed the 12th.
Still, "five-under on this course, and in this heat is good," he said.

In Gold Coast, Australia, American Amanda Blumenherst shot a 3-under-par 69 on Friday to maintain a share of the lead with Lim Ji-na of South Korea after two rounds of the ANZ Australian Ladies Masters.
First-round leader Blumenherst and Lim (66) had two-round totals of 9-under 135.
Australia trio Katherine Hull (70), six-time former champion Karrie Webb (69) and Tamie Durdin (68) were tied for third, two strokes back, along with South Koreans Ryu So-yeon (67) and Seo Hee-kyung (68).
Blumenherst, Hull, Webb and Durdin played most of their afternoon rounds in steady rain at Royal Pines. Up to 200 millimeters (eight inches) of rain hit the course earlier in the week.
When she finished her round, Blumenherst was shown on the tournament's computer leaderboard as trailing Lim by a stroke. But her score on the par-4 second hole was incorrectly recorded as a bogey instead of a par four.
It was the first time the former amateur star from Duke University had led a pro tournament after the first round, and she'll do it again Saturday in the last group.
Blumenherst's group was put on the clock with two holes left, caused mostly by a ruling needed by another player in the threesome early in the round. As a result, they had fallen two holes behind the group in front.

In Miami, Australia's Nathan Green and American Michael Connell fired five-under 65s to share the first round lead at the Honda Classic on Thursday, while Yang Yong-eun opened his title defense with a dreadful nine-over 79.
Green and Connell both returned bogey-free rounds in gusty, cool conditions at the PGA National Champions course in Palm Beach Gardens to lead Colombia's Camilo Villegas, Briton Oliver Wilson and Brazil's Alex Rocha by a stroke.
Fiji's Vijay Singh lurked one shot further adrift on three-under 67 with Americans D.J. Trahan and Bubba Watson.
Yang, who won his first PGA title with victory at the Honda Classic last year, got his defense off to a bumbling start and never recovered.
Playing the back nine first, the South Korean bogeyed the 10th then made a mess of the 436-yard par-four 11th taking a quintuple bogey nine.
Yang twice hit his approach shots into the water then three-putted, including a miss from inside five feet.
The PGA champion also had a double bogey and three more bogeys to go along with two birdies to finish ahead of just two players.
While Yang stumbled, Rocha, ranked 711th in the world, found his stride in the blustery conditions.
The Brazilian, who has spent his career battling for modest success on the Asian and European Tours, forced his way into the Honda Classic by surviving a pre-qualifying event, the Monday qualifier and then finally a playoff.