The All Blacks scored the game's first three tries and held the Pacific islanders at bay from there to finish 24-17 winners, claim their third gold of the 11-stop tour, and extend their lead over second-placed Argentina.
Cody Vai, Sione Molia, Leroy Carter and Ngarohi McGarvey-Black were the New Zealanders who went over the whitewash, less than an hour after their women's team secured their own gold medal by beating Australia.
"It's a different beast, Hong Kong Sevens," said Carter, whose three tries in the city put him on 26 for the series. "We did pretty poorly last time, so to get the win here... over the moon."
"I can't even remember the game, I was just in the moment."
Local favourites Fiji had made the final via a bruising and pulsating semi-final against Great Britain, with Terio Tamani's try sealing a 19-14 win in extra time.
This year's tour also serves as Olympic qualifying, with the top four teams automatically heading to Paris 2024.
The series heads to Singapore next, before Toulouse and the finale in London in May.
Carter said his side would look to build on the Hong Kong win.
"Anything can happen, but we'll definitely draw confidence out of this," he said, nursing a nasty cut to his left eye. "Taking it one tourney at a time, game by game."
Sevens tournaments hold a series of finals on the last day, as a chance for sides knocked out early doors to lift some silverware.
In the lesser finals Sunday, the bronze medal went to France, who beat Great Britain 19-17, while Argentina claimed fifth place, Ireland sealed ninth, and hosts Hong Kong finished 13th.
New Zealand women notch five in a row
A dominant New Zealand made it five wins in a row at the women's rugby sevens in Hong Kong on Sunday, beating Australia 26-17 in the final to get one hand on the overall series trophy with one round to go.
The Black Ferns had cruised their way through the weekend, swatting away early opponents and looking mostly untroubled by Fiji in the semi-final, which they won 31-5.
But in Australia, they found their most credible opposition, and both southern-hemisphere giants were in the game for most of it.
Stacey Waaka's second try of the match, in the fourteenth minute, made sure of the win, as well as making her the weekend's second-top scorer, after Aussie star Charlotte Caslick.
"We know it's always going to be close" against Australia, Waaka said.
"The best team on the day wins because of those little moments, and it's who can last the 14 minutes and we were fortunate to be on that side of the win."
The 27-year-old, who has 25 tries in the series so far, added that she hoped her country's win - at the first-ever stop for the women's series in Hong Kong - would resonate with younger women players.
"We're talking about paving a path for future generations," she said. "Hopefully there's many more years to come and hopefully the girls watching at home in New Zealand can be here one day."
Australia coach Tim Walsh echoed the praise for the "ding-dong battle" between the two neighbours but said the day's small margins were not in his side's favour.
"You know, it's just one moment that can be the difference between being disappointed and being on top of the world," he said. "That's the beauty of the sport and that's why we love it."
Olympic berths are also up for grabs during this series, with the top four teams automatically heading to Paris 2024, along with hosts France.
The final round of the women's series will be held in Toulouse in May, and Waaka said her side would take the time to "refresh mentally, physically" before then.
"We've got little things to work on; definitely not proud of every moment, but we can fix those going into Toulouse," she said.
New Zealand are 16 points clear of Australia in the series standings, and almost certain to secure the title in the French city.
They took gold at the previous four tournaments, in Cape Town, Hamilton, Sydney and Vancouver. They took home silver in the Dubai season opener, losing the final to Australia - their sole defeat all season.