Minutes later he's showing me a photo on his phone. And indeed, there he is, the actor best known as daggy but solid-as-a-rock Ben Rafter from the TV drama Packed to the Rafters standing next to America's first lady of song, Liza Minnelli. Apart from a few mentions in the gossip columns, this titbit of Sheridan's short but meteoric career is all but overshadowed by other achievements and media moments. But over the course of a couple of hours – and some tasty shared dishes – it's clear that Sheridan, to paraphrase Peter Allen, with whom his path has crossed, isn't quite the boy next door.

We're lunching at Magic Mountain Saloon in Little Collins Street, a sibling of Swanston Street icon Cookie, where early 20th-century industrial decor and raised marble benches are the setting for modern Thai food with an emphasis on barbecue grilling. If there's an identity crisis afoot here, it's thankfully not evident in the bold-flavoured dishes, which include cured kingfish with bitter melon, lemongrass and mint, a "sandwich" of grilled snapper with red curry paste and ginger, and a zesty papaya salad.

But back to Minnelli. Sheridan, still in his final year of studies at NIDA, had just signed up to Packed to the Rafters. Alongside house-cleaning, he had a more lucrative job singing at swish receptions for Macquarie Bank. At one of those functions in Hong Kong, a "larger than life character" introduced himself and handed him a business card. "I'll call ya," he said. "I thought, 'This sounds like a line to me'," Sheridan recalls, but four weeks later he was summoned to New York for a job. Minnelli was the surprise guest at a 50th birthday party, and "Hugh Sheridan from Australia", as he was introduced to the 700 partygoers, had the honour of opening for her.

It wasn't Sheridan's first brush with music royalty. His father is a jazz singer and supported Frank Sinatra at the legendary Ultimate concert at Sanctuary Cove.

"In fact he met Peter [Allen] there; he was the act before Sinatra," says Sheridan. "I grew up with all these stories. We even had this huge poster at home for The Main Event and a signed photo of Frank Sinatra."

When it came to his turn to open for Minnelli, the thrill for Sheridan wasn't just singing for her. He was being backed by Sinatra's band, whose members Sheridan is now naming. At 30, Sheridan is less known for his singing, dancing and cabaret acts than he might have hoped. But that may well change with the forthcoming ABC TV series and feature film The Divorce – a comedic opera from composer Elena Kats-Chernin and playwright Joanna Murray-Smith – and next year's jukebox-musical Dream Lover, in which he plays singer and songwriter Bobby Darin.

Sheridan was 16 when he won a place at the Australian Ballet School, leaving behind his close-knit family in Adelaide – he is the second-youngest of seven children – to live with an unnamed "crazy" woman in Melbourne who would count how many cornflakes he ate and from whom he ran away one night, sleeping on friends' couches and lounge-room floors.

"At the time it was chaos and I felt unhappy and scared. Now I look back and think what a challenging and exciting time of my life."

Accepted into NIDA, he thought his future lay  in the type of multidisciplinary work that his NIDA teacher, director Barrie Kosky​, did and continues to practise.

"I never thought I'd be cast in Packed To The Rafters. In fact a teacher at NIDA told me I'd never work in TV or film because 'you don't have the right look for it'," he recalls, adding that the clearly misguided prediction came from someone that had previously been thrown out of the school.

Still in their final year of acting school, he and fellow student Jessica Marais were cast as siblings Ben and Rachel Rafter in the drama that would proceed to be one of the most successful and popular series in Australian TV history.

Though he stuck with Rafters for 3½ years, returning as a guest for the show's later (and less successful) seasons, he, like several of his rising-star cohorts on the show, was already spending increasing periods of time in New York and Los Angeles focusing on his music career.

In 2009 he released an album Speak Love. He briefly returned to the screen in 2012 as the host of the unlamented I Will Survive, a Ten Network reality show about the search for an unknown talent to perform in the Broadway production of the musical Priscilla, Queen of the Desert. A harbinger of its fortune, the Broadway production closed before the show aired.

He also had a role as INXS bass guitarist Garry Beers in a successful Seven mini-series. He admits that the mantle of Ben Rafter hasn't been easy to shake off.

"I feel like that's finally letting go a bit, but certainly straight after I finished the show I felt a need to go away for a while and put my head down a bit. Rafters was the best start anyone could wish for ...  and we were lucky to get roles on it. My character was really loved, which was great, but I could see I have to get off this show or I'll never work again.

"I think people will always remember it, but more and more that I do outside of it, less and less people ask me about it. Having the opportunity to sing more is fantastic because while I had so many similarities with my character on Rafters, we have so many differences. He would be tone deaf and had two left feet for sure.

"The more you get to reintroduce yourself with other aspects of the arts and what I do people open up a bit. I needed to have that time and I spent a lot of time while waiting to get a green card in the US doing lots of workshops."

There is one recent chapter of his life, though, that didn't play out as planned, where given a chance he may have done things differently. Sheridan's younger brother Zachary was trekking on Mount Everest when an earthquake struck Nepal, triggering an avalanche on Everest, in April this year. It was early morning in Los Angeles and late at night in Australia when news broke. In shock and desperate for information, Sheridan tweeted that his brother was there.

A Seven executive contacted him and invited him to join a crew that was flying from LA to the disaster zone. Unsure at this stage if his brother was injured or worse, dead, and with the blessing of his family who had delegated him the grim task of finding out, he joined the Sunday Night team on the mission. While Zach was found safe though injured, Seven's promo for Moving Mountain promised it would follow Hugh and Dr Andrew Rochford in their bid to find Hugh's missing brother. Sheridan found himself at the centre of a backlash against Sunday Night and its promo, which were considered to have exploited Hugh's bid to find his brother, and to trivialise the immeasurable suffering of the victims, injured and homeless.

Sheridan says he was initially unaware – and later shocked – at the fallout, much of which centred around himself.

"It really hurt me when I heard it because I never conceived anyone would … I'd never judge anyone who'd been in that position. But we can be tough," he says of Australia's media.

"At the time I was so worried about my brother that I hadn't thought about the effect the experience would have on me. Coming back I was confronted because I was so oblivious. I had no say [over the promos]. The wrong messages got out."

He says that Zach didn't want anyone to come and get him after he was found. "So I decided to wait in Kathmandu until he arrived and that did put us under a lot of pressure because Seven had already promoted a show they hadn't finished, and what they wanted was a shot of us being reunited. It was horribly stressful, but the main stress was worry about my brother."

Though his brother had a lucky escape, the psychological fallout has been challenging, Sheridan says. But helping out while the Sunday Night crew got the story they had travelled so far for also proved a rewarding experience.

"I never thought of myself as very practical, but I think I'm pretty good in a crisis. It was total destruction, so unbelievable to see what had happened. I was digging and moving bricks with these little children, whose schools had gone.

"I'd never considered before that if something happens I could get on a plane and fly there and use my hands. We're so encouraged to steer clear when something goes wrong."

The bill, please

Magic Mountain Saloon

62 Little Collins St, city; 9078 0078

Mon-Thurs 7am-3am (kitchen till midnight); Fri 7am-3am (kitchen till 1am); Sat 8am-3am (kitchen till 1am); Sun 8am-3am (kitchen till midnight).