Matt Wright sold MCT Automotive Group, owner of the cars website Cars4Us, to Toyota Tsusho Corporation for the hefty sum just six years after starting the company.
The business has ballooned from humble beginnings of four people working from a Brisbane warehouse that could hold seven cars to turning over roughly 4000 vehicles a week, with tidy annual revenues of about $500 million.
What began as a wholesale operation soon branched into sales and trade-ins to the public, with a commitment to offering people more than regular dealers for their old car, while tapping into the rising digital habits of car buyers.
"When we started, the largest online car buying company was buying 60, 70, cars a week. We got there within 60 days," Mr Wright told AAP.
"Fast forward to today, six years later, we buy 350 on a bad week, but realistically, 400 to 450 vehicles a week."
The flagship lot in Brisbane's Eagle Farm has ballooned to hold about 1000 cars, the second-largest in Australia.
MCT's scale aims to condense the car-buying experience potentially into a single trip, while the turnover rate supports competitive prices.
"Typically, when you're trying to buy a car, it's a Saturday, you've got four dealerships written down, you spend an hour on each dealership, driving between each one. It's a nightmare," Mr Wright said.
"What we like to do is get people in and you just stay with us and if you don't like the car you came in to buy, we've got three, four, five other variants or combinations of that car."
Mr Wright came to Australia from the UK as a 20-year-old backpacker and quickly fell in love with the country.
"I was taken aback and couldn't imagine anywhere else I would want to spend my life," he said.
"Being the other side of the world on your own really accelerated that learning for life and, quite possibly, is the reason why I was successful in business, perhaps at ... an earlier age than most."
Another key to Mr Wright's performance is his work ethic, and like many founders, he regularly clocks up working weeks of 80 to 100 hours.
"I've learned to refocus and adjust what I'm spending that time on, and through the continued support of a growing team of good people around me, and good leaders in the business," he said.
"But workload, I would say, has never really changed."
And despite his $120 million windfall, Mr Wright will continue doing what he does best to assist with the handover to Toyota Tsusho, Toyota Group's Tokyo Stock Exchange-listed arm.
"I'm excited to be able to stay and help steer the business over the next couple of years which, regardless of selling it, I want nothing more than to see the company, in the group, reach its potential," he said.
"It might be the biggest retail site on the east coast, it might be the biggest car buyer in the country, but it really does have a lot more potential than that."
The future might be unclear beyond this particular horizon, but the young entrepreneur knows one thing for certain: there's more work to be done.
"I'm certainly not contemplating a life that doesn't involve running more businesses, running my own businesses, but I'm fully committed to these guys for a couple of years," Mr Wright said.
"My father's 75 and still works, you know? I'll be doing the same."