"I looked at the daily rate and sent a photo, it evolved over a while, after the first audition I waited three weeks for a call back to audition next to Cliff Curtis."
It turned out he was a powerful force in front of the camera, reciting the script like a professional, though he had been nervous about meeting one of his acting idols.
"Cliff came up and gave me a hug and a hongi, he said; 'come on, let's be a couple of Maori guys playing a game'."
A former gang member, Hapi broke away from that way of life in 1997 - but was able to draw on his background to bring depth to his character.
As Ariki, the brother of psychiatric patient and chess whiz Genesis (Curtis), he pushes his eldest son into a gang out of a misplaced desire to see him safe and secure.
"I could relate to that environment I was in one of the country's gangs early on. Ariki has got a bit of a situation, because he's dying, and he feels he doesn't have anything to offer his son, so he wants him to be patched - he cares really deeply, but there's limited options."
Born in Murupara, east of Urewera National Park, and raised by his staunchly matriarchal grandmother until he was 14, Hapi is Tuhoe on his mother's side and Whakatohua on his father's.
Mostly skilled at physical labour, Hapi had some knowledge of directing through a course at Unitec, but hoped to continue down the acting road.
"If feedback is anything to go by, I'm hoping I will have the chance to do more."
He was already a fast favourite with fans, who were stopping him in the street asking for photos, he was also receiving a lot more attention while busking in Auckland.
"I was pretty embarrassed and shy at first, but when I see people's reactions, it makes me feel pretty good inside."
The Dark Horse was recently accepted in the Toronto Film Festival, taking Hapi's captivating performance to the world.
• The Dark Horse is on at Reading Cinema in Napier, see: readingcinemas.co.nz for more information.