He showed promise last year, but has busted the door down in 2018, a key part of the Warriors' remarkable start to the season. He's the local boy made good, who could become a cult hero at Mt Smart.
It's been a remarkable rise for the kid from Avondale, who didn't start playing league until he was 13.
"I didn't play when I was young," said Afoa. "All my childhood I never played. I was just a ball boy. All I did was catch the ball and put it down."
Afoa looked up to his older brothers, but was content running the tees and collecting stray kicks, until eventually the fuse was lit just before high school.
But nothing came easy, and the large whanau made for a humble background.
"The hardest thing was probably providing for everyone," said Afoa. "We never had the flash boots, or anything like that."
Afoa also had to walk to training, up to 45 minutes each way, though his dad was usually by his side.
"It was a long way, I remember that," said Afoa. "But my dad would always take me, bring me back, it didn't matter how late it was. At a young age you don't really notice that, but after you realise Dad really wanted us to succeed."
His elder brothers didn't make it in league, and went in a different direction, which fuelled Afoa's fire.
"We were all competitive. It was hard but you had to make your own path. I wanted to work hard and get where I wanted to go.
My brothers went down a different path and I didn't want to go that way. I made a tough choice. I'll take the hard way, as I had a dream that I wanted to play NRL."
Afoa moved from Bay Roskill to Mt Albert, where he was first noticed by manager Stan Martin.
"He kinda came out of the middle of nowhere," said Martin. "A lot of kids are spotted at 13 or 14 but Bunty was a bit later. He was a late bloomer. But even back then, he was consistent. There was never a lot of difference between his good games and his bad games."
Afoa made his NRL debut as an 18-year-old in 2016, playing four games that season. He managed a further 17 matches last year, mainly in the second row. To his credit he coped well, but is flourishing now in his natural position.
"I'm in the middle now ... it's where I belong," said Afoa. "That's where I always wanted to play and I finally get that chance. But I can't take my foot off the pedal now ..."
Afoa credits trainer Alex Corvo's influence — "he was always telling us to never give up, there is always something more in you" — and teammates Adam Blair and Simon Mannering for his improvement this season.
"They have taught me about conserving my energy," said Afoa. "It's about being smart with it. You don't always have to burst it all out. It's all about the key moments when the team needs it, like a tough carry, or tackles that go unnoticed."
Afoa says Blair has also helped him see a "clearer picture" on the field, among the frenetic action in the middle. Afoa has always been quick, but this year he has also got stronger. He's already becoming a popular figure among the fan base, with his fearless running style and ability to drive on after contact.
It's quite remarkable, given he is 21 years old and played his 31st match yesterday.
In the toughest area of the field, Afoa is averaging 100 running metres a game, and almost 10 metres off every carry. He is also making 24 tackles a game — with barely any misses.
"He's probably one of those guys that is a bit unsung when the wraps go out for the team," said coach Stephen Kearney. "He's a young guy, still learning about himself, still learning about the role for a middles, and doing a wonderful job. He wants to get better, he wants to learn, and as long as he has that attitude he will always improve."
