Branches are opening in the United States and tomorrow marks the official opening of three New Zealand branches, two in Auckland and one in Wellington.
Life could have been much different for the young man with the big story. Prince's parents were born into poverty in rural Sri Lanka. They gained an education through the free schooling system in place across the country in the 1940s.
His parents were the only students in their school to move past year 10, and both went on to achieve top marks.
Prince's parents met at university in England after being granted scholarships - he was born in Scotland a few days after his mother completed her PhD in economics. The political upheaval in Sri Lanka meant they were loath to return with a young family, so they relocated to Australia.
There, Prince also made the most of a free education system. He excelled and left school at 15 to pursue a degree in literature.
A few years later he was accepted for medical school at Monash University in Melbourne, where his dream of bringing great Mexican food to Australia was born.
"I'd grown to love Mexican food, and realised that it could be a big new trend."
He started working as a chef at a Mexican restaurant to fund his studies and learn about the food.
"I deliberately sought out that job - I'd fallen in love with the food and wanted to learn all I could."
And he wanted to create a restaurant that allowed people to taste the real flavours of Mexico, not the TexMex, sour cream and refried beans version available at the time.
Over six months, he fine-tuned a menu that was to be the basis for his restaurant. And at the end of his second-to-last year at medical school, he came up with an audacious plan to launch his venture.
"I decided that when I moved back to Canberra, where my family was based, over the holidays I would set up a Mexican restaurant. It was 2005 and I was 21."
Australian entrepreneur and philanthropist Dr Sam Prince
Armed with a mere $12,000, Prince took over the lease of a failed restaurant on less-than-salubrious Lonsdale St.
It took three weeks of 20-hour days to set up the restaurant. He bought all the essentials secondhand and scrubbed and painted the premises himself.
And he hired a graphic designer to ensure the aesthetic was right front of house.
"At the time, Lonsdale St was a bit of a dive," he says. "And Canberra wasn't as adventurous as Melbourne when it came to food. The whole thing was kind of mad."
Mad maybe but equally prescient. Prince believed Mexican food's time had come. He was right.
The restaurant was a hit and a potential business partner emerged proposing a franchise arrangement. The Zambrero empire was born and today boasts more than 60 restaurants in Australia, Thailand, the US and now New Zealand.
Working full-time as a doctor and overseeing a restaurant empire may seem like a full life, and for a few years Prince happily went about his dual roles. But he started to feel something was missing.
"Noel Pearson [a leading indigenous leader] asked me where I sat on the political spectrum. I contemplated this for a while. On the far right you have people who celebrate individual excellence, which isn't a bad thing. On the left you have people who celebrate fairness, which is also not a bad thing."
The evolutionist in him took a journey back to cave people. He decided our prehistoric forebears had a mixture of both qualities. Individual excellence coupled with giving and generosity seemed an ideal way to conduct business.
Informed by this new philosophy, and armed with cash from his franchise, Prince started to work out ways to combine the two in his business ventures.
"Ban Ki-moon was Secretary-General of United Nations in the late 2000s. He identified the lack of access to technology as one of the biggest hurdles to students in developing countries," he says.
"This really resonated - my parents had benefited so much from their free education. It seemed the ideal way to give back to the people of Sri Lanka."
He approached the Sri Lankan Government with a proposal to provide funds for humanitarian work, and in 2008 went to Sri Lanka to help put a project into action.
Through the Emagine Foundation, Prince eventually helped build 15 IT complexes in Sri Lanka, Vietnam, and far north Queensland schools.
Working alongside aid organisations to get the projects off the ground was eye-opening.
"As I worked with aid workers I became aware that financial, religious and political motivations have no place in humanitarian work. I came back to Australia with the knowledge that work of such a nature must be undertaken without an agenda.
"If you go in without thinking of the implications of your actions, you can make things worse for the people you are trying to help."
After the Emagine Foundation projects, Prince and his growing team spent time researching aid organisations they could pair with for future humanitarian work.
They settled on Action Against Hunger, which provides food and clean water to people in areas of conflict, famine or disaster.
Together they developed the Plate 4 Plate initiative, whereby money from each burrito or bowl sold supplied a plate of food where it was needed.
A third organisation, Stop Hunger Now, came on board to pack and deliver the food.
Children in Nicaragua receive food from the Plate 4 Plate charity, run by by Dr Sam Prince
"Plate 4 Plate has provided food to people in more than 65 countries throughout the world. Some of the missions are ongoing, some in response to short-term need."
The New Zealand Zambrero franchises will provide funds for a charity closer to home - Kids Can, which helps disadvantaged young people - as well as sending money overseas through the Plate 4 Plate initiative.
As well as launching Zambrero, Prince is the founding director for Mejico, a higher-end Mexican restaurant that also has a humanitarian slant. Another restaurant is in the offing, called The Village, but Prince isn't sharing details on this venture yet.
In 2010, he set up the charity One Disease, working with indigenous Australian communities to help eradicate scabies. And his most recent project, Life Letters, has been set up to help people understand the role genetics plays in their makeup and help with early identification of illness.
Prince says the recent developments in genetics have unlocked huge potential for preventive, personalised medicine.
Life Letters aims to harness the power in this knowledge to improve health outcomes for people across the world.
"Correct and responsible understanding of individual genomes could be used to predict cancer, and prevent disease. We have Nobel Prize winners on our board; Life Letters is set to launch in Asia next year and we are predicting it could soon become one of the biggest businesses in Australia."
Prince is based in Sydney but he plans to spend much of next year in the United States.
He says the transition from struggling medical student to the head of a company with more than 1000 staff still takes a little getting used to.
"It wasn't that long ago that I was working in a restaurant and struggling to pay my bills."
But he says a motto shared by his mother, whom he considers his greatest influence, has provided him with huge inspiration: "Expand your life to the limits of your mind and expand your mind to the limits of your life."
Prince acknowledges that everyone has a different path.
"People need to be authentic, aware of their history and to align the values to aspire to with the way they live.
"Everyone has a different life path, but in my experience when your aspired values meet your lived values, this equals happiness."
