Two years ago, Melbourne’s AS Patric couldn’t even get a rejection slip for his book, Black Rock White City. Not one of the big Australian publishers responded when he sent it; he couldn’t raise a pulse.

Now that same book, eventually nabbed by small independent publisher Transit Lounge, has won Australia’s premier literary prize, the $60,000 Miles Franklin award. It edged out the presumptive bookies’ favourite The Natural Way of Things by Charlotte Wood, and the three other Miles Franklin shortlisted books: Hope Farm by Peggy Frew, Leap by Myfanwy Jones, and Salt Creek by Lucy Treloar.

“Any of those books on the shortlist could have won,” Patric told Guardian Australia. “It’s an amazing shortlist, and I’ve met all the authors – they are incredibly generous and warm and talented. I feel like the merit here really is about the shortlist and after that – winning – is a subjective thing.

“In another year with another set of judges, anyone else could have won.”

Patric pays no mind to gender, and what is made of the male/female ratio of shortlisted authors: “In the last four or five years the shortlisted books have been mainly by women, and the best books have been by women. It’s not as though there have been books by men that have deserved to win – I don’t see any absent books, the best writers in the country were those women.

“But it’s not about being women or men, it’s about writing great books. I would hate to think of myself as a ‘male writer’.”

For Patric, 44, the prize rewards his belief in the importance of representing the working-class immigrant experience, a motif he finds missing in Australia’s literary landscape. His parents were immigrants from the former Yugoslavia, as are the two main characters in his book.

According to the Miles Franklin judges’ comments, Black Rock White City – which tells the story of Jovan and Suzana’s resettlement in Melbourne, after they flee war-torn Sarajevo and the death of their children – is “a fresh and powerful exploration of the immigrant experience and Australian life ... it explores the damages of war, the constraints of choice, the possibility of redemptive love and social isolation amid suburbia”.

Patric said he had been living with these characters for six years: “Someone asked me, ‘How do you deal with such darkness for such a long time?’ And yes, there is a lot of darkness, but it is also representative of what I love, the love between two characters; it’s a genuine love story, an immigrant story,” he said. “I was wanting to represent [my parents] in some way, to give voice to their experience so I know it hasn’t just evaporated into nothing, that it has some sort of significance.”

For him, the book – the first novel he’s had published – also fills a gap in Australian culture. “A lot of literature [in Australia] is about the middle class, and I wonder why we have so few people speaking for working-class life – not because it would be some kind of virtue, but because it’s interesting!

“Why don’t we see more immigrant stories? We have all this richness in our culture and yet you look around publishing and there are so many rural historical experiences, and everyone’s Anglo Saxon.”

The win, he said, was “the most momentous news of my life”, like being awake in a dream. “I had to say to myself, it’s really true. If you have a privileged background and you went to the right school and had the right parents, you might think [when you’re shortlisted], ‘maybe I’ll win’.

“But if you come from working-class suburbs, from the western suburbs of Melbourne like I do – a child of immigrants – you think it’s not even a possibility. It’s ridiculous that you could do something like that.”

There’s joy too for the small and independent publisher Transit Lounge. A Miles Franklin win can mean between 20,000 and 40,000 extra sales for a title.

A delighted Barry Scott, Patric’s publisher, said his company was committed to publishing books that reflected multicultural Australia. “It’s great to have that recognised,” he said. “This is a powerful story about Australia’s suburbs and how immigrants feel like they have not only lost their past, but also their future. Having said that, there’s a lot of hope in this story.”

He said Transit Lounge had planned an extra print run of 12,000 to cope with demand for the Miles Franklin winner, but “we’ll probably have to print more”.

For Patric, such an unexpected prize comes with its own challenges. “Of course [I’m] mostly happy, but there’s a lot of anxiety as well. You know, if you look into the lives of writers to see what they’ve done right and wrong, and how that affects the choices they make ... sometimes something great happens and it’s a disaster for them.

“I want to keep myself in a quiet and humble spot so I can actually keep writing. If you get an idea of yourself as being an important writer, you can pretty much write off your writing ... and I think you become a much less compelling literary voice.

“These are just some of the concerns you have when, after many, many years of absolute obscurity and oblivion, you suddenly feel a bit of sunlight.

“Well, a lot of sunlight actually.”

• This article was amended on 1 September to refer to Black Rock White City as AS Patric’s first published novel, not his first published book.