Grossi Florentino, the grand dame of Bourke Street, recently celebrated 90 years of serving Italian food to Melbourne diners. How does a restaurant survive that long? According to today's custodians, the Grossi family, it comes down to respect and a certain amount of flexibility.

"We're a much more grown-up city now than we ever were before," says chef and restaurateur Guy Grossi. "Once a upon a time, it was the big, old restaurants that were the successful ones. Then along came the newcomers, doing great things. And for a while, we exalted in the new and forgot about the old. Now I think we're more like a European city, where we just respect and appreciate both."

There was a time when a man would require jacket and tie just to enter Florentino's mural room. So imagine the pressure the Grossi family felt when they took over in 1999. Anything with that kind of longevity was always going to be a challenge. "All of a sudden it wasn't just a business for us anymore," says Grossi. "It was a responsibility. We couldn't let people down."

For the first year the Grossis didn't really feel like it was their place. There was a feeling they weren't up to it – especially when regular customers, who had started visiting Florentino long before the Grossis took over, were resistant to change. "Obviously we wanted to bring our own touch. It was a difficult time, and it was a big turnaround for us. Things will change and you just have to keep up."

The Grossi family has been deeply embedded in Melbourne's Italian hospitality scene – and by extension, the Florentino – since the early 1960s, when Guy's father, Pietro, newly arrived from Italy, started in the kitchen at Mario's Restaurant in Exhibition Street. On his first day, during a break between lunch and dinner, he popped around the corner to the Florentino cellar bar for a little glass and a plate and it left an impression on him.

"There seemed to be this connection, and I always just loved the place," says Grossi. "Coming into the city, even as a youngster, I was in awe of it. It's just something that seemed to me to be aspirational. I first visited the Florentino as a guest when I was 18 years old. I went there purposely, because I thought wow, this is just going to be an unbelievable experience. And being a young chef, I wanted to experience as much as I could."

All of a sudden it wasn't just a business for us anymore. It was a responsibility. We couldn't let people down.

Guy Grossi

Working outside hospitality was never really a conversation Grossi had with his family or even himself. "Dad would take me to work and I'd end up helping out," he says. "Always doing the shittiest jobs in the kitchen: sweep the floor, peel potatoes, clean beans, stuff like that. And I actually didn't like it at first – Dad worked really hard and I thought, 'I don't think I ever really want to do this.'"

But he soon got over that, and graduated from Box Hill TAFE in 1980. Back then, as Grossi was moving up the ranks as a young chef, the Italian restaurant scene was more broad. "Regionality was something which hadn't really been explored. And it was a hard sell. But we started dabbling with it because I really liked the idea of having people understand where that heritage of a particular thing was from."

At 25, after a brief run working for legendary Swiss-born chef Hermann Schneider at fine-diner Two Faces, Guy Grossi left to run his first restaurant, Quadri, in Armadale.

He's the first to admit he was a little young to be owning and running his own place and discourages young chefs from following suit. Still, "it was really good for a first time out. We just did our own thing, on a really low budget, just buying the food on a day-to-day basis, taking some money and doing it again with hardly any staff."

The Grossi empire – it now encompasses the grand Grossi Florentino dining room, the Grill, the Cellar Bar, salumi bar Ombra, wine bar Arlechin, casual eatery Pezzo, Merchant restaurant in Collins Street and Garum in Perth – has always been a family affair. Guy Grossi runs the business with his sister Elizabeth and brother-in-law Chris Rodriguez. His son Carlo works on the floor, and his daughter, Loredana, is across design – it's a close-knit tribe.

"Now that I'm working with the kids again, I get to spend heaps of time with them which is really nice," says Grossi. "I didn't necessarily get to spend a great deal of time [when they were growing up]. I'd basically say goodbye in the morning and they'd be in bed when I got home. So it's really nice to have that connectivity again now."

It's not all laughs, hugs and prosciutto, though. "We do have our fair share of barneys," he says. "That happens. But I think we generally get along pretty well. We usually thrash things out, and then you just hope you make the right call."

Growing up in such a dedicated hospitality family, all their table conversations naturally revolved around restaurants – "what you could do with this and what you could do with that.

"Even now, when we get together, we talk about work," says Grossi. "And a lot of people might think that that can get really boring but it actually doesn't. We get excited about it. On one occasion somebody said, 'Look, let's stop talking about work and let's talk about something else.' And then everything went quiet."

Quickfire corner

Music to cook to: The crooners (Frank Sinatra, Dean Martin). I love the Doors as well. Lou Reed, the Beatles. I really enjoy the house filled with cooking smells and atmosphere. I say, "Come on – someone set up the music and charge it up."

Late-night snack: Midnight spaghetti from Arlechin. Especially if you've had a few vinos.

Secret ninja skill: Man, what do I do? I don't stand on my head or anything like that but I am a closet singer. I love karaoke.

The last book you read: Peter Gilmore's new book, From the Earth. It's so well researched. I'm learning a lot from it.