He's the latest City Kickboxing talent to break into the UFC, who may soon be joined by yet another fighter from the famed Auckland gym, but life could have quickly spiralled out of control for Navajo Stirling had he not found combat sports.
Stirling, who last week earned a UFC contract with a devastating KO victory over Phillip Latu on Dana White's Contender Series, has been booked to fight Tuco Tokkos in Tampa Bay in December.
That is a long way from Upper Hutt, just outside New Zealand's capital, Wellington, where Stirling grew up and later saw his life slipping away before his eyes, that was until he set his sights on becoming a professional fighter and found the purpose his teenage years craved.
"When I was 15/16, I used to be a sheep. I was a follower. I never did drugs or anything, but I used to drink all the time and my idea of drinking alcohol was getting blacked out drunk and drinking until I was sick," Stirling told ESPN from his Auckland home.
"I soon realized I was doing that because I had no purpose in life; I knew I was meant for something, but my thing was to push the problems of the world to the side through the drink. But once I realized that and I got into fighting and I realized this was something worth fighting for, I was able to tone back on the drinking and really put myself into something that was worth it.
"And suddenly I was excited to wake up just from the decision alone; I hadn't achieved anything yet, but I was so focused on becoming a UFC fighter or just a fighter in general, just the decision alone made me excited to get up and go to work; it made me excited to push through everything, I was like a man possessed."
Stirling certainly looked like a man possessed when he delivered the thumping left hook to Latu's chin that sent the American tumbling to the canvas, so too the referee who immediately stopped the fight to prevent Stirling from doing any more damage to his opponent.
The Kiwi, who only had his first MMA fight at the end of 2022, began his combat journey in kickboxing, dominating the local scene around Wellington before realising that if he was to make a career out of fighting he would need to switch sports.
"I've always wanted to be the best in what everyone cares about," Stirling said. "I knew that I wanted to be a fighter as a career and although I started out as a kickboxer, I soon realized that kickboxing was going nowhere, there was no hype in it, and that's why I transitioned to MMA.
"I was a little worried when I first started that I wouldn't like grappling, but when I got into grappling I realized how much I loved to grapple. Grappling is awesome, and I just try to utilize the most exciting aspects of fighting.
"And yeah people were like 'you should fight in Glory or One' but I don't really care about those, it's all UFC and that's where all the best fighters are. I want to fight the best with the most hype, the most entertainment, there is nowhere else for me to go but here [the UFC]. So I set my eyes on that and that's how I got to this point."
Having exhausted the training options around his hometown, Stirling knew there was only one place to go in New Zealand if he was to truly fulfill his potential in MMA. So armed with a newfound confidence from his part-time bar job and the people skills learned along the way, he contacted City Kickboxing coach Eugene Bareman and hasn't looked back since.
The move brought him onto the same mats as former middleweight champion Israel Adesanya and fellow City Kickboxing stars Dan Hooker and Kai Kara-France, while another teammate Aaron Tau will on Tuesday night [Wednesday morning AEST/NZT] get his own shot at the Contender Series - and a possible UFC contract proper - when he fights Elijah Smith.
Having two fighters graduate to the UFC from the same gym down in one small corner of the world in consecutive weeks will be no mean feat, but Stirling says it shouldn't really surprise anyone such has been the trail Adesanya, in particular, has blazed.
"Israel was like a crazy pinnacle part of the next generation of Kiwi fighters," Stirling told ESPN. "Eugene didn't even know if there would be anyone coming up after Israel, but he has shown the New Zealand people, who are usually a bit of soft-spoken nation, that we can talk a little bit more, push our chest out and be proud -- that's what I've learned.
"And now other young Kiwis are starting to pick up on what I'm doing, and we've got a bit of a trickle effect going - I believe there will be a lot of great New Zealand fighters for years to come.
"To me, he's [Adesanya] like the Michael Jordan of New Zealand combat sports. It's not even just the sport, he's changed the thinking part of it, he's altered the culture of it, he's bringing a new wave through. I'm just fortunate enough to come into the backend of it now and I'm taking the torch and hopefully pushing it on to everyone else, because everyone is genuinely getting behind me in this nation and I feel that."
While Adesanya is approaching the twilight of his own MMA career, Stirling is very much at the genesis of his. Like CKB teammate Kara-France, Stirling too is of Maori descent, his first name Rongotehengia a tribute to that family lineage, leaving a question as to why he goes by Navajo instead.
"My two siblings and I have; our first names are very long Maori names. They're family names. But we go by our middle names and my parents have always loved really different names," he said.
"My brother was named after Shaquille O'Neal and my dad was really into western movies, cowboy movies, old westerns, so that's where the name Navajo comes from. But our first names are very long, they were complete nightmares in roll call back in primary school.
"Even Navajo is hard for people, so Nav is what I go by; but that's a little about us. I actually used to hate my name when I was a little kid, I wished I had a normal name and looked like other Maori; I wanted to fit in. But then I realized I wasn't meant to fit it; I'm meant to be different to everybody and it's cool that I have embraced that now."
Produce more knockout victories like the one he delivered last week, and the MMA world will have Stirling's unique name at the tip of its tongue.
For now, though, it's back to doing what he does best, putting in the work on the CKB mats to prepare himself for his first UFC fight proper.
"I don't know too much about him and I'm not really one to dissect my opponents," Stirling said of the fight with Tokkos on Dec. 14. "I will look at his stuff eventually, but I'll leave it to the coaches and the corners to break him down. I'm back in training anyway, and the intensity of my training varies depending on how far I am out from a fight.
"But I credit a lot of my success to just being in the gym non-stop, whether it be very easy or very hard, time on the mats is king to gaining a lot of success. I really look after my body and I've got a lot of time until then, so I'm going to sharpen up some of the things that I need to upskill."