With his latest role as a corrupt cop in the comedy War on Everyone, he is arguably Hollywood’s biggest Latino star. He talks about speaking out in defence of the little guy – and how the church helped his script-reading

Like all of us, Michael Peña is talking about Donald Trump. “But what do you think?” He looks at me curiously. I blurt out something garbled about the stealthy rise of fascism. “I just can’t believe he’s made it this far. That’s my thing. I mean, having absolutely no experience. It’s like this guy just picked up a tennis racket and now he thinks he can beat Djokovic.”

Peña is a movie star, although you might not know it from his sweatshirt and Nikes, or his hey-brother affability. He turned 40 this year, his face boyishly round but with grey whispers in his beard. He is also the son of Mexican immigrants, so abused in the speeches of the US presidential candidate. His parents were undocumented – illegals, Trump would say – starting a family in North Lawndale, Chicago, before securing green cards.

“He just wants to be elected,” Peña says. “So that’s him trying to relate to the majority of white Americans.” And do most white Americans feel the same way? He rephrases the question. “Is there an immigration problem? There’s an immigration problem in every country that has money, in that people there have a problem with immigration. Look at England. You guys have money, and maybe you can call that luck, and maybe you don’t think about how lucky you are. Me, I’m an American, and I live pretty well. But go down to Mexico and a lot of people really don’t. So what, we’re going to blame them for trying to get out?”

It’s a quirk of modern culture that Hollywood actors get a platform to address the world, and Peña is one of the few Hispanics who gets to use it. Or at least one of the few everyone knows is Hispanic. He plays only Latinos: Rick Martinez in Ridley Scott’s The Martian, Trini Garcia in the second-world-war epic Fury, Mike Zavala in End of Watch, the verité police thriller that probably gave him his best role. The names are important. If his character doesn’t have a Latin name in the script, he says, he asks for it to be changed. “So maybe some Hispanic kid might hear that and be inspired.”

Kids are not the obvious market for his new film, the caustic comedy War on Everyone. Created by the Irish writer-director John Michael McDonagh, making his American debut after the success of The Guard and Calvary, Peña stars as Bob Bolaño, a grandly corrupt Albuquerque cop. “People will be offended if they don’t realise we’re taking the piss,” he says.

Peña sits in slightly different positions according to what is being discussed. With politics, he hunches forward. His career brings him upright. Remembering his childhood, he leans back, stretches out. He tells me three stories from growing up in North Lawndale, where gangs were everywhere – the Latin Kings, the Gangster Disciples – and his parents grew tomatoes on the side of the house. In the first, he is five, and his mother is removing him from his school, Assumption, having realised the nuns were downgrading his tests because he liked to draw rather than sit still. In the second, he is eight and has been given his first bike. “My dad got it from Toys ‘R’ Us for less than a hundred bucks.” Peña took it to nearby Douglas Park. He acts out being punched in the chest, hard. “I owned it for half an hour. They didn’t even run off with it. They strolled.”

Facebook Twitter Pinterest Peña with Alexander Skarsgård in War on Everyone.

In the last story, he is a 14-year-old with a gift for maths and the support of his parents and brother, enrolled at a private school an hour across Chicago. He loved it, although he regularly found himself without the cash to buy lunch. To make up the shortfall, he mimicked teachers for 25 cents a time. “I once asked these other kids: ‘Do you feel lucky that you have money?’ They said: ‘I don’t even think about it.’ They weren’t being assholes. It was the only life they knew.” After two years, he left. The family could no longer afford it.

Now, he likes to think of himself as frugal, but worries he might be cheap. He always tips 20% he says, more to himself than me. His childhood left him with a sense of how people exist in different worlds. While he’s sure some of the kids from Assumption ended up a block away, in Cook County jail, a classmate from private school became a senator.

Earlier this year, in the middle of the debate about racial diversity at the Oscars, he told journalists it was a “champagne problem”. Besides, he asked, why wasn’t anyone mentioning that the director of The Revenant, Alejandro González Iñárritu, was Mexican?

“I’m into looking at things from the other point of view,” he says. “And if you look at who votes in the Oscars, mostly older Jewish guys, they’re going to vote for stuff they relate to. Do they relate to NWA? I doubt it.” He and his eight-year-old son never agree on music, he says, to which I say, but wait – you can’t equate race and a difference in taste between generations.

Facebook Twitter Pinterest Peña with Jake Gyllenhall in End of Watch. Photograph: Allstar/STUDIOCANAL

“But it is generational.” He mentions his son again. On Martin Luther King Day this year, he says, he explained to his son how African-Americans had been treated in the fight for civil rights. “And he burst into tears and called me a liar. ‘People wouldn’t do that, Dad!’ He’s a bright kid, but the whole concept of racism is just bizarre to him. And with the Oscars, the voters get younger, and diversity gets better. I mean, I hear what people have said. I get it. I just want to be real about it.”

The one thing Peña never seems to talk about publicly is being a Scientologist, despite joining the church in 2000. But he says he’s happy to tell his story. He took his first step out of concern about his drinking – “I wasn’t an alcoholic, but I was doing it too much” – entering the detox programme Purification Rundown. “And then there was the next thing, and the next thing. For me, it isn’t religion like a belief; it’s practical things you do.”

Was it also a way of navigating Hollywood as a young actor without connections? “Not really.” Instead, he credits another Scientology programme, Study Tech, with making him a more confident reader. “Which made me a better actor because I felt like it helped my understanding of scripts.”

But he must be aware of the endless controversy that surrounds the organisation? “Yeah, but I don’t read that stuff.” He’s aware of it, though? “Yeah but – OK, imagine we’re friends, you and me. Buddies. And there’s a tabloid story about you. There’s no way I’m going to read some fucking tabloid story about you.” He looks straight at me again. “Especially when I know it’s misinformed.”

War on Everyone is released in the UK on 7 October