Kully Thiarai, the new artistic director of National Theatre Wales, wants to know why theatre persists in “telling the stories of the few when you can tell the stories of the many”. Her first season at NTW, announced on Monday, sets out to correct that by reflecting the experiences of the millions of ordinary people whose lives have been touched by the NHS – the brainchild of Ebbw Vale MP Nye Bevan, who used the Welsh miners’ medical aid scheme as a blueprint for the nationwide institution in 1948. NHS 70, an ambitious seven-strand, multi-platform celebration, will take part across Wales and online in 2018.

More immediately, Thiarai is preparing We’re Still Here, a piece created with Common Wealth theatre company about the Tata Steel works and the futures of those who work there. The show will find NTW returning to Port Talbot, the site of one of its greatest hits, The Passion, which starred Michael Sheen and played out across the streets of the town in Easter 2011, a year after the company was formed. It was NTW’s equivalent of the National Theatre of Scotland’s Black Watch, one of those rare shows that people still talk about with awe. But Thiarai isn’t worried that going back to Port Talbot might look like an attempt to relive past glories.

“It’s not The Passion 2. It’s a very different piece,” she says, adding “You can’t allow yourself to be less ambitious and less brave because of what has already been done and the successes of your predecessor. [She took over last year from founding director, John McGrath.] We will always go where there feels most need and most urgency. We’re Still Here is the right show at the right time because the steelworks is a story that is still unfolding. The globalisation that is having such an impact on a small town in Wales is also affecting communities all over the world.”

Common Wealth are already embedded in the town, working towards a piece that will be performed in a warehouse close to the steelworks, and which will feature some of the local people who were involved in The Passion. “It’s about deepening and moving on our relationship with the people of Port Talbot,” says Thiarai who knows all about the effect of changing industry on people’s lives. Her own father was at one point a labourer at the steelworks in Smethwick.

Before arriving in Cardiff, Thiarai had worked with Red Ladder in Leeds, Contact in Manchester and Cast in Doncaster. Doncaster has been one of the most deprived and least culturally engaged places in the country. Her solution? To open Cast up as a “living room” for the entire town, a place where everyone was welcome.

“When you run an arts building it is often seen as the artistic director’s playground, when it should be seen as a place for the public to play,” she says. “We are only custodians of the space.” In Doncaster, a theatre that few wanted or welcomed has gradually become a bustling place. Thiarai smiles wryly as she points to the fact that a lot of her career has been spent doing jobs that others in theatre haven’t wanted to do, often in contested spaces such as Cast or firefighting in crisis-torn organisations. “It can have benefits. Sometimes when a situation needs sorting you are allowed to do things and take risks that you might otherwise not have been allowed to do,” she says.

“There is talent everywhere, there is creativity everywhere, there are just not the opportunities everywhere,” Thiarai believes. “There were no opportunities for people like me growing up in Smethwick, so I’m always going to fight for those opportunities for others.”

Raised in a West Midlands town, where she was familiar with being chased down the street by racists, Thiarai knows what it’s like to grow up in a household where there are no books and no access to the arts. Her route into theatre was accidental. She began training as a social worker, but was sidetracked into theatre after discovering the Theatre in the Mill in Bradford and seeing companies such as Gay Sweatshop, Red Ladder and Phoenix Dance.

Thiarai’s background – still unusual in a theatre world dominated by white, middle-class, Russell group graduates – has given her a refreshingly different perspective on the sector. “It has never been about me thinking about what play do I want or should I direct next to further my profile, and always about thinking about what needs to be done in this place and at this time.” It’s an approach that those with a more strategic outlook on their careers could well learn from, not least because the appointment of Thiarai at NTW demonstrates that her approach chimes more with the times as theatre re-evaluates its purpose and place in the community.

“One reason I was drawn to this job is because NTW have always been so open to exploring the ideas and issues of communities who seldom get their views heard. I’m interested in how we can push the boundaries of the art form of theatre in relation to community and place.”

She believes that all our futures might depend on harnessing the creative potential of not just the few who have access to the arts, but the many who do not. “Discovering theatre made me think about the world, my own place in it, and to articulate what I felt about that. NTW can offer that to other people, and it’s more important than ever because we live at a time when the world is shifting so fast – economically, socially and technologically – that it can feel frightening. Retreating into nostalgia isn’t the answer. It’s our imaginations that will help us find the way to respond.”

• We’re Still Here is at Byass Works, Port Talbot, 15-30 September.