After a first round TKO win against Aussie Casper Turner and third round TKO win against another Aussie, Brett Jeffery, in his first two fights Leutele, 24, scored a unanimous points decision win against Cameroon's Christian Tsoye in the final.
Tsoye fought at the Commonwealth Games on the Gold Coast earlier this year and was the Pan African heavyweight champion.
"Christian had more fights than me during his amateur days. I threw hard shots at him and he took them well so I kept throwing as much as I could. He was as tough as me but I got my timing right with my punches," Leutele said.
The 2011 national youth super-heavyweight champion, who is aiming to be the New Zealand heavyweight champion by the end of the year, said he hoped his success across the Tasman will open the door for more opportunities on the international stage.
"I'll sit down with Rod this week and discuss where we can go from here," Leutele said, referring to his manager and another member of his coaching staff Rod Langdon.
One of the country's most experienced trainers, Langdon, was impressed with Leutele.
"Toa displayed enormous maturity throughout the night. His final was a battle but Toa threw heavier and cleaner punches and the crowd loved it."
"This was Toa's first taste of international experience as a professional and he grabbed it with both hands. This is huge for him," Langdon said.
Leutele's previous fight before travelling to Melbourne was in March when he scored a third round TKO against Canterbury heavyweight Ali Loto.
That was Leutele's first fight in two years after a spell and his second professional bout.
A former Samoan boxing champion, Leutele snr was pipped by former New Zealand professional fighter Lance Revill for a berth on New Zealand's 1974 Commonwealth Games team.
He has been keen to see his son represent New Zealand since he first took up boxing in 2008.
It was the second taste of international glory within three weeks for Langdon.
Last month another of his professionals, Beau O'Brien, scored a fifth round TKO victory against Fijian Silevini Nawai in their fight for the WBF Asia/Pacific middleweight belt in Fiji.
A Napier Boxing Club clubmate of O'Brien and Leutele, 14-year-old Lachlan Cooper recorded his first win in four fights at a tournament in Naenae at the weekend.
A 48kg cadet class fighter, Cooper, beat a Wairarapa opponent with a third round TKO.
"Lachlan used his height well," trainer Ryan Whittaker said.