Hamilton's achievement came the day after Wanaka-based snowboarder and Winter Olympian Julianne Bray won the Quarterpipe Invitational Air competition, held under lights at the Snow Park on Friday night.
Hamilton, an 18-year-old from Auckland's North Shore, was the only New Zealand male to make it to the finals of Saturday's half-pipe competition, in which he finished eighth.
His half-pipe performance followed his 11th placing in Friday's slopestyle finals, and his combined points tally has lifted him clear of the other riders.
Hamilton said it was a great feeling to be the No 1-ranked rider but stressed there was a long way to go in the series.
Three points separate him in the overall rankings from second-placed Stephan Maurer, of Switzerland.
The New Zealand event is the first on a six-stop global series, with competitions in Australia, Canada, Europe, the US and Japan to come.
Hamilton said he was happy with his performance in Saturday's half-pipe but frustrated he could not nail his second and third runs.
"I had a great first-up run and that usually takes the pressure off, because you have one in the bag.
Then you can go out and give it everything in the last two runs.
It's all or nothing."
Unfortunately for Hamilton, and New Zealand, he could not land the necessary technical tricks he needed in the half-pipe to secure a higher placing.
However, his eighth placing gave New Zealand a presence in the men's competition after last year's winner, Mitchell Brown, failed to make it through to this year's finals.
Brown finished 22nd after bowing out in the half-pipe semifinals, in which he struggled to find the speed to create the aerial amplitude (height and air time) necessary for riders to earn the high-scoring points for jumps and technical tricks.
Bray followed up her Friday night quarter-pipe win with a strong performance in the women's half-pipe, finishing fifth, in her first major competition in a year after a return from knee surgery.
Bray was joined in the female half-pipe finals by Kendall Brown, the younger sister of Mitchell, who finished sixth.
Jamie Anderson was the star of the event.
The 18-year-old American won the half-pipe competition on Saturday to go with the slopestyle title she won on Friday - the first time she has recorded back-to-back competition wins during an open.
The slopestyle specialist scraped into the women's half-pipe finals as the eighth and last qualifier.
On her first run she laid down a score of 84.25, which included the final's best trick, an inverted backside 540.
Anderson told the Otago Daily Times after winning she had considered not entering the half-pipe competition.
"I smashed my head on the quarter-pipe during the invitational jam [on Friday night] and wasn't even going to enter because I really didn't feel that great."
The win was her first in a major half-pipe open event.
Anderson's first run left the women's field chasing her, including compatriot Kelly Clark, who had dominated in the semifinals.
Clark struggled to maintain her form in the final and slipped to third after a couple of missed grabs and a fall.
The mistakes allowed China's Jiayu Liu to grab second.
Japan's Kazuhiro Kokubo won the men's half-pipe competition with a score of 92.50.
Markus Malin, of Finland, was second and Daisuke Murakami, also of Japan, third.
