Matt Damon's politics owe a great deal to his mother.
The first time Nancy Carlsson-Paige saw her son featured in a glossy magazine, she was appalled. "My beautiful boy is being used to sell products," she told a newspaper. "He is just a cog in the capitalist system." She'd never even read a magazine like Vanity Fair before, her son explains. "She's a professor. If it's not the Nation, she doesn't read it. And she said, 'This thing is nothing but page after page of adverts for products that nobody needs!'" He chuckles. I'd love to know what his mother makes of his latest film, Elysium, a big-budget sci-fi action thriller packed with set-piece fights and expensive pyrotechnic violence. "Hmm, well, my mom's big on non-violent conflict resolution," he grins.
Damon has travelled a long way from the Boston commune where he grew up in the 70s and 80s among five other families who were, if not quite hippies, then firmly on the countercultural left. Today he is one of cinema's all-time highest-grossing leading men, voted World's Sexiest Man by People magazine, with his own star on Hollywood's Walk of Fame. A father of four (three daughters, aged seven, five and three, and a stepdaughter, 15), this summer he is moving his family from New York to Los Angeles, and the challenge of giving them a childhood that remotely resembles the one he enjoyed is about to get even harder.
Choosing a school has already presented a major moral dilemma. "Sending our kids in my family to private school was a big, big, big deal. And it was a giant family discussion. But it was a circular conversation, really, because ultimately we don't have a choice. I mean, I pay for a private education and I'm trying to get the one that most matches the public education that I had, but that kind of progressive education no longer exists in the public system. It's unfair." Damon has campaigned against teachers' pay being pegged to children's test results: "So we agitate about those things, and try to change them, and try to change the policy, but you know, it's a tough one."
At 42, Damon's face has scarcely changed since he first became famous, its features so regular that he could be almost anyone. Just days before our interview, he and George Clooney were photographed popping into a council-run gym in Cambridge, on a break from shooting a new movie nearby, and while most movie stars out in public look haunted by their own fame, Damon somehow always looks like just one of the boys having fun. But he is worried that it will be tougher to live as an ordinary person in LA. "It's a little unnerving. It's going to be a very big change for us."
In New York, he explains, "I've been really lucky. I'll completely forget that I'm a celebrity. And then something will happen and I'll go, oh, right. Literally days will go by in New York where I'm seeing the same parents drop off and pick up at school, and where everything just feels completely normal. I'm going to the Starbucks, and people know who I am, but it's the same baristas there, and they're calling out everybody's name. It's just our neighbourhood spot. So I'll fool myself, and then something happens."
Damon's Argentinian wife was a bartender in Miami when they met 10 years ago. "I think marrying somebody who's not a celebrity, it just takes a lot of the pressure off." His old friend Ben Affleck hasn't been quite so lucky. "Ben's wife, Jennifer Garner, she sells a shitload of magazines in the midwest. Magazines that – Ben explained this to me – you and I have never heard of, but that appeal to a mom in the midwest, who for some reason identifies with Jennifer and wants to know what she's doing as a mom. As a result of that, there are always five cars outside their house."
He's banking on his family being too boring to attract much attention, even in LA. "The narrative is, OK, he's married and happy and they have kids, and there's not really anything else to the story, the story never changes."
But if he's wrong? "Well, if that part is really bad, then we'll leave. It's just not worth it. There are things I'm willing to give up, you know, but there's a limit."
He's also uneasy about the incredible wealth that must define his children's lives. "Our kids are growing up with more privilege than we had; that's true for most of my friends in LA. I don't know any actor who grew up with any particular privilege, so everyone wrestles with this. And I think a lot of times it's about being patient with your kids."
He remembers once staying in an apartment without air-conditioning when his stepdaughter was 10, and she simply refused to sleep. "And we sat there in a huff for a second. And then my wife and I looked at each other and went, 'Oh my fucking God, she's never slept in a house without air-conditioning. This is not her fault; this is our fault.' And I went upstairs and explained to her that all over the world there were kids right now who were sleeping and they never even knew what air-conditioning was. And that, when I was a kid, it was this hot every night in the summer, and I got a washcloth and I wet it. And I explained how her uncle Kyle and I would bump into each other in the bathroom in the middle of the night rewetting our washcloths. And she was laughing. We talked for, you know, 10 minutes, and I turned the light off and she was already asleep.
"It's something we talk about a lot, but I think ultimately it's about giving them an understanding of the world. So at least they can get some context for where they fit into everything."
Damon co-founded the safe-water charity water.org, and hopes his children will join him on field trips to Africa when they're older, but he also worries about ending up a Hollywood rentagob activist. "Yeah, there's the people who, you know, feel like, 'Shut up and sing,' " he grins. "People feeling preached to by privileged actors. I get that totally. I don't want some Hollywood actor finger-wagging at me, telling me what I should and shouldn't do."
The trick, he's finding out, is to deploy humour, evidenced in a recent spoof press conference where he announced he was going on toilet strike until the whole world had access to proper sanitation. "There's just no reason so many children should be dying, but if you say that, people go, 'Oh, shut the fuck up', you know what I mean? So you say, 'I'm going on a toilet strike'," and he starts to laugh.
Movie stars with Damon's sort of body of work routinely say they need to make big-budget blockbusters so they can earn enough money to make politically important or artistically interesting low-budget, leftfield films. It's a common formulation, but always makes me wonder exactly how much money these stars can really need. And when the actor is as serious about progressive politics as Damon clearly is, how does he square such an inflated notion of "need" with ideals of equality?
Damon looks puzzled. "I've never taken a job for money."
Never? "Not since early on, starting out, no. I've passed on a lot of huge-money jobs. Money doesn't enter into the decision-making. If I do a big blockbuster, it's about how big an audience you'll get, and where you can take them."
It must be my turn to look surprised, because he adds, "You know, I lost money last year."
What does he mean?
"Well," he says, looking perfectly relaxed, "I earned less money than I spent."
Elysium, it is safe to say, will not lose Damon money. The big-budget sci-fi action thriller is set 50 years in the future, when Los Angeles has been reduced to a post-apocalyptic slum and the super-rich have fled our ravaged planet for a ruthlessly exclusive space station, Elysium, where everyone owns a machine that can cure illness and injury within seconds. LA's desperate and dying will pay anything for a place on a craft bound for Elysium, only to be shot down by military rulers who consider their privilege a right, and self-preservation a moral absolute.
In other words, it is an allegory: a movie about global injustice and immigration that looks like your average sci-fi extravaganza but is artfully crafted to make western audiences identify for once with the poor and destitute who gamble with their lives to reach the west every day. Even if some viewers miss the allegory altogether, Damon says, "I don't feel like anyone's going to feel like they're the ones on Elysium." And for all its fantasy elements – the cyborgs, the magic medical machines – he doesn't think its futuristic vision is too far-fetched.
"I honestly think the world's going to look very different in 20 years. I mean, could you imagine," and he holds up his mobile phone, "that this has access to more information than the president had 15 years ago? There's more computing power in this than the strongest computer in the 1970s."
Does he find that exciting or scary?
"That part's really exciting, yeah. You know, they – Google or whoever – they're at this place where face-recognition software is at 84-94%. Soon you'll be able to walk into a bar and look around and your glasses will tell you who everybody is. So, yeah, it's going to get weird. And I don't know what the implications of all that are. And some of it's certainly creepy. But exciting. I think it's an incredible thing."
Isn't the phone he's holding up a not-very-new-model BlackBerry? "Oh, yeah," he concedes with a rueful grin. "I'm still with the dinosaurs. I gotta get an iPhone. But the difference between a luddite and a tech geek at this point is, like, six months."
It wasn't always obvious that Damon's career would lead him into action blockbusters. It's now 16 years since his breakthrough role, in a film he co-wrote in his 20s with his childhood friend and co-star Affleck, hoping it might be a way for them to get noticed. Good Will Hunting won them both an Oscar, and launched A-list careers that, depending on who you believe, saw Damon soon stall in the commercial doldrums of credible character acting, while Affleck struck blockbuster gold; or, alternatively, established Damon as a discerning artist while Affleck squandered his promise on cheap celebrity, famous chiefly for dating Jennifer Lopez. Damon doesn't buy either narrative, but does concede that by 2002 things weren't looking great for him. All The Pretty Horses and The Legend Of Bagger Vance had both been box-office flops, and the thriller he'd just finished had clocked up so many reshoots that Hollywood gossips were already writing it off.
"It didn't look good. All the signals were that it was going to be a bomb, and it would have been the biggest of all of the bombs. That was a big budget, so now people are going, 'OK, he's about to lose a lot of money for people.'" But Damon and the director kept watching the film over and over, trying to work out how to fix what was wrong. "It's like tinkering in your garage at that point. We're both completely devoted to fixing it, like two kids pulling the lawn mower apart and putting it back together again, trying to figure out what would make it run the best. And we did."
The thriller was The Bourne Identity. It didn't strike instant box-office gold, but Damon thinks that may have helped, "because so many people had a sense that they discovered it for themselves". It still might never have made the leap to global franchise had Damon not scripted a new ending to its sequel, The Bourne Supremacy, just two weeks before its release, replacing a limp finale with a more playful scene whose last line fans still love to quote: "Get some rest, Pam. You look tired." The final reshoot was a mad scramble, but for Damon it was "really, really fun. I mean, I just got adrenaline, the rush telling you the story." He rewrote bits of the third Bourne film, too, and says he loves every aspect of film-making, but opted against having any involvement in the fourth because he didn't think any plot could compete with real life by then.
"The first one was about a guy who's part of a secret programme, who assassinates people. And so now they make it legal under Bush to assassinate people. OK, well, shit, now what are we going to do? So by the time we got to the third one, the big reveal is that Bourne shoots this guy without knowing who he is, and they pull off his mask, and oh my God, it's an American. Well, now, of course, it's on the front page of the paper: we've killed four Americans [in drone strikes abroad]."
Damon has been a passionate public supporter of Barack Obama and is confident that his healthcare reforms will rescue America from the iniquities Elysium dramatises. But Edward Snowden's surveillance revelations have just emerged when we meet and, Damon admits, "It just seems to have taken this weird, Orwellian turn. It's surreal. I don't know where we are now."
He does, however, have a theory about how these developments have happened under Obama's presidency. "I think it's tough for guys who weren't in the military," he says. "One, their manhood is kind of challenged on some level, I imagine, and they allow themselves to get bullied. And two, they're just politically afraid of either looking soft or looking incompetent, so they overcompensate."
Could disillusionment put him off campaigning for another presidential candidate? "No, I'm sure I will. As disturbed as I am by a lot of the things that Obama has done and is doing, I would not have preferred a Romney presidency, that's for sure. The alternative is even more frightening."
• Elysium opens in UK cinemas on 23 August 2013
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