From starting as one-third of a promising secondary school front row in Auckland, his burgeoning career ground to a halt shortly after graduating, before a doctor's ultimatum inadvertently set him back on course to the coveted All Blacks jersey.
Tu'inukuafe has just been recruited to join Steve Hansen's squad for the three-test series against France as an injury replacement for Crusaders loosehead Tim Perry - a call-up, the 25-year-old strongman admits, he "didn't see happening any time soon".
He first came to prominence in 2010 as part of the massive First XV front row at Auckland's Wesley College, where he propped alongside fellow Chief and All Black Nepo Laulala but a short few years later he was married, "working a desk job" and had given up on the game.
By 2014, his weight had ballooned to 170kg and his health was deteriorating.
"I was living in Māngere when I got married and I just chucked on the weight. I wasn't playing about 2013 or 2014. So I was just sitting around. I had a desk job, working security. That Auckland life, so I put on the weight," Tu'inukuafe told Radio Sport's Nigel Yalden.
"I talked to the doctors about feeling a bit weird, like health wise and they just gave it to me straight. They said, 'you gotta lose weight or you're going to end up…"
His cousins convinced him to give rugby another go – as an easy way to shed some of the unwanted kilos.
"They were playing at Takapuna rugby club. They told me to join them," Tu'inukuafe said.
"I thought it would be fun playing with the family. And that rugby would be an easier way to try and lose weight instead of doing it on my own."
Tu'inukuafe rediscovered his love for the game and as his waistline decreased, coaches and fans again started taking notice.
He was playing for North Harbour in 2015 and after spending a season with French club Narbonne, Tu'inukuafe was recruited into the Chiefs squad late last year by coach Colin Cooper in a development capacity.
Without a Chiefs contract at the start of this year's Super Rugby season, Tu'inukuafe's debut didn't look promising.
However, a string of injuries to the Hamilton side's props saw him called onto the bench in just the second match of the season.
Now, nearly 40kg lighter, Tu'inukuafe is an All Black.
"I got a missed call and then a text from the [All Blacks] manager Darren Shand. I just called him back and he said congratulations. It was unreal," Tu'inukuafe said about his call-up.
"I couldn't really say [what Hansen and Co saw in him]. I guess I'm different now. I have my wife and kids supporting me.
"There's been a lot of ups and downs, as everyone goes through. But you've gotta go through them to push through whatever comes up. I've just been blessed. From where I've come from."
He'll be star-struck when he meets his new teammates in camp in Christchurch at the weekend, Tu'inukuafe admits.
"I'll definitely be nervous meeting everyone. I'm sure they'll introduce themselves. But I already know who they are.
"It's going to be pretty buzzy."