It has been five years since Irish director Ivan Kavanagh released his last film, the horror caper The Canal, which is somewhat of a sore point for the director. Kavanagh has spent years writing and working – but unfortunately, Hollywood is a fickle old town.

“I was writing a TV series based on Henry James’ The Turn Of The Screw,” he reveals Kavanagh. “I thought it was the best thing I ever wrote. I wrote the pilot and the first seven episodes, and just before it was going to go into production, they pulled the plug. Wasted two years of my life on that! But that happens a lot in America.”

Kavanagh’s patience and persistence was also tested during the process of getting his new western, Never Grow Old, to the big screen. He started writing the film in 2007, but had many false starts along the way.

“It was very ambitious,” Kavanagh says. “It had a fairly large budget for an Irish production, and nearly happened a couple of times. It was almost a Hungarian-Irish production, almost an Italian-Irish production with Damian Lewis and Mickey Rourke, and was weeks before production when it fell apart! But I was actually glad it happened that way, because I was able to make three feature films, including The Canal, within that time. I don’t think I would have been ready to make it in 2007.”

Shot largely in Connemara, Never Grow Old stars Emile Hirsch as Irish carpenter and undertaker, Patrick Tate, living on the outskirts of a small frontier town on the California trail during the 1849 gold rush. When outlaw Dutch Albert (John Cusack) and his vicious gang take over the town, Patrick starts profiting from the mayhem and bloodshed – but his complicity starts catching up with him.

The past year has seen the Famine-set revenge western Black 47, and now this frontier western with an Irish lead character. For Kavanagh, the appeal of the western lies in its exploration of greed, revenge, fear and belonging – themes which will always feel prescient, particularly in America.

“When I started writing it in 2007,” he reflects, “George Bush was still President and there was a lot of xenophobia towards Muslims. It seems to be part of the American psyche – xenophobia and intolerance and fear of the outsider – which is really strange from a country that was founded by immigrants! And now we have Donald Trump with Mexicans – nothing changes. The themes remain the same. So the film is about the founding of America on violence and blood and robbed land from the Native Americans. Patrick is a character who embraces the American Dream totally, and it turns into a nightmare.”

What’s often missing from narratives about Irish immigrants going to America during this period is how they became complicit in racism, xenophobia and violence, but Patrick’s actions allude to the idea.

“Patrick wants to be accepted,” says Kavanagh. “The Presbyterians made him live outside town because he was Catholic. And they made him convert. So he’s delighted to be welcomed, by anyone. But you do see that Patrick has no problem living on land stolen from the Native Americans. There’s a throwaway line in the preacher’s sermon at the very beginning, where he talks of clearing the land 500 miles in all directions of savages. That means xenophobia and murder, but Patrick doesn’t think about that. I suppose if you are an oppressed people like the Irish, and when they came en masse because of the Famine, many look for people lower than you. It’s a dark side of human nature.”

Though Kavanagh may have missed out on Damian Lewis and Mickey Rourke, he was delighted when John Cusack came on board as the stoic and vicious villain, Dutch Albert.

“We got on very well,” says Kavanagh. “He’s very political, a very smart guy. It comes into his process; he likes to intellectualise everything. We would be up at two in the morning talking about the motivation behind every word and gesture of his character. I write an in-depth history for all of the characters. I sent John that, and he came back with a complete notebook of his own ideas. He said he saw Dutch Albert as the personification of capitalism.”

Kavanagh reveals that Cusack’s commitment meant staying in character onset, which could be intimidating – but Kavanagh is happy to roll with actors’ eccentricities and idiosyncrasies.

“John wasn’t always easy to be around,” says Kavanagh. “He wanted to be by himself, to keep the intensity – he wanted the other actors to be intimidated by him. But he got the performance. People talk about star quality; John Cusack’s the only person I’ve met who has it. When he walks into a room, there’s a hushed tone.”

Casting Emile Hirsch came with a different challenge. In 2015, he was charged with aggravated assault after attacking Paramount executive Daniele Bernfeld, strangling her to the point of unconsciousness. Hirsch spent 15 days in jail and went to rehab. When he was cast in Once Upon A Time In Hollywood, his first high-profile role since the assault, Bernfeld’s friend Jameela Jamil tweeted that Hirsch “left [Bernfeld] with three years of PTSD and never paid for her treatment, and still hasn’t apologised to her.”

How did Kavanagh feel about casting an actor surrounded by such a controversy, particularly in a film about violence, complicity, exploitation and greed?

“We talked a bit about it, and to be honest I’ve never met someone who is more remorseful about something, and shocked at what they did,” asserts Kavanagh. “It completely changed his life – he gave up alcohol, he hardly ever goes out now, he’s just concentrating on his son and his work. I felt like he was genuinely sorry and remorseful. I think Emile’s just a guy who did something terrible while on alcohol and drugs. On set, he’s genuinely a nice guy to everyone. The idea of living in a wold without forgiveness is unbearable to me.”

Is it within the gift of film directors and people unaffected by the original crime to do the forgiving, I counter, or the victim? And does forgiveness mean having a movie career – which is a privileged position few people ever get to experience?

“I think it depends on how you look at it,” Kavanagh says hesitantly. “That might be more a question about the criminal justice system in America. He is doing a lot of other work. He’s very good in the film, and he was very good to work with.”

• Never Grow Old is in cinemas now