James Calombaris is proud of his dad and wanted to take a friend to Gazi, one of his father’s Melbourne restaurants, for lunch.  “Have you booked?” asked Calombaris, of MasterChef fame, when James revealed his plans over breakfast. He hadn’t.

“I said ‘James, if you don’t make a booking, you are not getting a table.’” Calombaris’ partner Natalie raised her eyebrows. James is five years old and still at pre-school. Nevertheless, following his father’s instructions, he picked up the phone and booked. “That for me is a little lesson,” says Calombaris. “I want him to understand the value of life like I was taught.  It’s about working hard. Nothing comes on a platter for him. There is no golden spoon.”

Calombaris, 38, is nothing if not a hard worker, but he is propelled by something more than that – a relentless, restless energy that makes him fuss over every detail, from the menus in his restaurants to the tidiness of the serving areas and even the direction of the toilet paper. He doesn’t walk so much as bounce. “People say, ‘Why do you bounce so much?’” he says. “I need to. It’s my energy.”

For someone who doesn’t read books and limits his staff to five emails a day – “Just pick up the phone and ring!” – Calombaris has become one of the most successful restaurateurs in the country, expanding his empire as other celebrity chefs’ collapse. The Melburnian oversees 12 eateries, from the high-end Press Club to souvlaki chain Jimmy Grants, which recently expanded to the Gold Coast. His ambition is to emulate Merivale boss Justin Hemmes,who runs a stable of over 40 bars, pubs and restaurants.“He’s a legend,” he says. “If I could get to his point one day, well, great.”

He is the first to admit, chefs don’t always make good businessmen. His secret is to be upfront about his failings, and join forces with people who are strong in areas where he is weak.

Paperwork is a particularly weak point. “BAS, tax, this, that, landlords, rent,” Calombaris says with mock confusion. “I quickly learned to surround myself with people who could do that. One of my business partners knows how to build restaurants, cost cut, save, and do deals on leases. The other brings a totally different thing to the equation. We are three different people, but around the table there’s an amazing chemistry.”

The chef has experimented with expanding his brand and clocking up guest appearances.Later this month, he will appear again at Oh My Greek Week, a five-day celebration of Hellenic culture in Melbourne. Recently, he also collaborated with homewares brand Salt & Pepper for a collection of non-stick, hard-anodised aluminium cookware.

He has learned enough about the business side of the industry to know that when restaurants go under, as many do, it has a powerful ripple effect. He believes the hospitality industry deserves more financial support from the government.

“In Melbourne,(chef) Shannon Bennett and I employ close to 700 people combined,” he says. “If we went under tomorrow, would the government bail us out?” Next, Calombaris plans to expand into Sydney. It will be a Greek eatery, working name Electra, in Surry Hills. His chefs are already in Greece, researching the menu, but it’s not expected to open until late next year.

“It’s my first major foray outside of Melbourne, which is pretty scary and daunting,” he says. “I can’t put my finger on why, but I know it is different.  We need to knead it and work it and understand it and adjust accordingly.

“I want it to be accessible. There will be no rules, no ‘You must be in at eight, you must give your credit card.’ We will create options – you can book, you can walk in, you can get pick-up or delivery. It will be a Gazi-esque type place. It’s grungy, it’s gutsy, it’s not about making everything 90 degrees and perfect.

“It’s about focusing on flavour, being energy-driven, and a night out where you go, ‘How cool is that?’”

Calombaris juggles all this with MasterChef, the cooking show on Network 10 that made him famous. He has signed on for another three years.

“I’m not going to sit here and bulls**t you – of course it brings customers to the restaurants,” he says. “But it’s adouble-edged sword. People’s expectations are through the roof.”

He believes the key to the show’s longevity is its innocence and integrity. Not for them the catty contestants whose personalities outshine their food.

The three judges, Calombaris, Gary Mehigan and Matt Preston, have made it clear they won’t stand for that. “We are the mafia of our show. We literally run the ship,” he says. “I don’t want to spend time with people who are ignorant, arrogant, not caring. We don’t need the cliched types.”

Calombaris has often said that food is his religion. To be sure, he is a zealot, evangelising in his many different temples almost every waking hour of every day. Except Sunday.

Sunday, he devotes to his family. Although, often that involves food, too. Sometimes he will take his kids, who are banned from eating fast food such as McDonalds, down to a family-run burger restaurant in a Melbourne park.

“We have chips – I don’t hold anything back,” he says. “What I do teach them is my religion, as you would if you were Buddhist or Catholic. My beliefs are about food – it’s a whole food diet. It’s real, it’s tasty and it’s yummy.”

Calombaris has never had resistance from James on his McDonalds ban, even though he sends him to fast-food parties with a healthy packed lunch. “He’s been so brainwashed,” he says. Michaela, his three-year-old, is not far behind.

Even the Calombaris kids’ grandparents are devotees to this food religion, and their mother Natalie, originally a nurse, is studying nutrition. “Their grandparents have a massive backyard with chickens, beehives, vegetables, fruit, everything,” he says.

“My father-in-law makes his own sausages, his own wine. My kids, they taste wine. They’re not sculling wine, but they taste it. They stick their finger in. We have this binge-drinking epidemic in Australia. It’s horrible. When I am in Europe, I don’t see drunk people. It’s not something that’s taboo, then when you turn 18 you go nuts.

“You are happy to stick how many teaspoons of sugar in a soft drink into a kids’ mouth, but something made from grapes – and yes, it’s fermented – you’re not happy to give them a little taste?”

Not everything Calombaris attempts is successful. He and Natalie are not married, despite his efforts. “I keep asking her, and she keeps saying no.”

He doesn’t, however, agree that chefs make terrible husbands. “I think it’s about the chef making sure they are with the right person, someone that understands this life.”