M ark Ruffalo is angry. “Donald Trump is public enemy number one,” says the man who plays Hulk in the Avengers films, leaning forward in his chair. “Everything that comes out of his mouth is a lie. This dude is standing in the way of anything significant happening in the world as far as climate change is concerned. It’s f***ing terrifying and it keeps me up at night. Most people don’t realise what’s coming. Countries are freaking out about Syrians coming, a few thousand Syrians. We are approaching mass extinctions, food systems failing, hundreds of millions of displaced people looking for places that are hospitable.” He pauses, breathes. “In my country, half of the political system doesn’t believe in [climate change], in science. I’m inviting the rest of the world to get involved in our next election, because the fate of the world is in the f***ing balance. And you can print that.”

Lacking the protective carapace that film stars tend to bring to interviews – that mix of rehearsed anecdotes and smiling reticence – Ruffalo is as passionate and politically minded as he is charming. At 52, he looks great. Dressed in a crisp white shirt, his hair tousled and peppered with grey, he is trim and tanned, with a kind, crumpled face and dark penetrating eyes that are at once concerned and unsuspicious. He hasn’t shaved.

We’re in a hotel in central London to discuss his excellent new film Dark Waters. Based on a New York Times long read, this is the true story of corporate defence attorney-turned-environmental activist Robert Bilott and his struggle to expose the DuPont chemical company, which used toxic materials in a number of its products despite knowing full well how harmful they were. Ruffalo, a long-time environmental activist himself, not only stars as Bilott, but is also the film’s producer. “Rob’s journey was really interesting to me,” says Ruffalo, who recruited the fêted auteur Todd Haynes as director. “The fact that he was a criminal defence attorney for a chemical company. What was it like for a guy to be on the inside of that culture swimming against the stream? He knew all the tricks that defence attorneys know and he had the time and the budget and the expertise to win.”

Ruffalo spent a lot of time with Bilott trying to understand what makes him tick. “Rob’s a very emotionally withdrawn person,” he explains. “He’s not what you imagine as a hero. Every other person trying to save the world has so much ego; they’re gregarious, they’re charming. There’s almost no ego in him.”

As played by Ruffalo, Bilott is dogged and self-effacing, a crusading everyman with a jutting lower lip and awkward posture. It’s the kind of role Ruffalo excels in. Although he first made his name as a loveable slacker in romcoms such as 13 Going on 30 (2004) and Just Like Heaven (2005), he has since become the master of empathy, capable of peeling characters back to reveal a wounded vulnerability. Think of him as the tired, dishevelled homicide detective in David Fincher’s Zodiac (2007). Or the doomed Olympic wrestler Dave Schultz in 2014’s Foxcatcher. Or the twitchy, terrier-like reporter in the Oscar-winning smash Spotlight (2015).

Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher Show all 10 1 /10 Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher 10. Infinitely Polar Bear (2014) In the wake of The Avengers, Infinitely Polar Bear marked a further attempt to launch Ruffalo as a studio-movie leading man, following the 2013 musical drama Begin Again. He rises to the challenge – even if the rest of the film is very indie-by-numbers. Playing a bipolar father to two young girls, Ruffalo sources a compelling unpredictability, flipping between deadpan eccentricity, casual cruelty and unbridled joy. His lovely, textured humanity remains his greatest on-screen weapon. Sony Pictures Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher 9. XX/XY (2002) Potentially the greatest test of Ruffalo’s likeability occurred in this 2002 indie, which cast him as a lusty narcissist incapable of recognising his own failings. Playing one third of a spectacularly wrong-headed trio of lovers which slowly implodes over the course of a few weeks, Ruffalo refuses to embody total villainy but instead a very naturalistic kind of ignorance. He plays his character as every well-read asshole you’ve ever met at a university party, and it’s a performance that proved early on the depths of his range. IFC Films Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher 8. Foxcatcher (2014) Ruffalo has arguably the least interesting role of the trio at the centre of Foxcatcher. That he somehow delivers the film’s most fascinating performance then qualifies as a major victory. As the murdered Olympic wrestler Dave Schultz, Ruffalo radiates goodness – a man raised to be respectful and kind and work hard for great rewards. He is therefore someone incredibly uneasy about ever stepping out of line. Alongside Steve Carell’s inexplicably Oscar-nominated scenery-chewing performance as the convicted killer John du Pont, Ruffalo’s natural subtleties were even more powerful than usual. Sony Pictures Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher 7. My Life Without Me (2003) It feels notable that the filmmakers who have most often cast Ruffalo as scruffy, troubled and sexually attractive characters are women. Isabel Coixet’s tender weepie My Life Without Me is no exception. Playing an open-hearted loner who falls in love with a woman he doesn’t know is dying (played by the wonderful Sarah Polley), Ruffalo is the film’s secret star. There’s a weighty surliness to his performance here that is also oddly exciting, Ruffalo perfectly in tune with the complexities of Coixet’s movie. Sony Pictures Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher 6. Zodiac (2007) The real-life detective portrayed by Ruffalo in this David Fincher classic served as the inspiration for Dirty Harry. He plays him with a similarly brusque masculinity – all snark, cigarettes and fatigue. It’s one of Ruffalo’s most charged performances, with much of its power stemming from how the character gradually spirals outward. He transforms from somebody doggedly by-the-book into someone tortured by a mystery he can’t solve, and it’s thrilling to behold. Warner Bros Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher 5. 13 Going on 30 (2004) Considering his innate agreeability and non-threatening masculinity, it’s no surprise that Ruffalo had a romcom phase. It is surprising, though, when glancing at his career in totality. Ruffalo’s romcoms were by and large of the C-list variety – cast alongside genre queens at their least interesting (the Reese Witherspoon vehicle Just Like Heaven, or the Jennifer Aniston bomb Rumour Has It…), or romancing not-very-funny actors struggling to diversify their filmography (as in the infamous Gwyneth Paltrow airplane comedy View from the Top). But then there’s 13 Going on 30 – a candy-coloured femme spin on Big, with Ruffalo at his most endearing. He plays spectacularly well off Jennifer Garner’s dizzying, all-limbs portrayal of a 13-year-old stuck in the body of a grown woman, and has never been more warm and natural. Columbia Pictures Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher 4. Dark Waters (2019) Dark Waters finds Ruffalo at his Ruffalo-iest, playing a righteous, determined attorney standing on the right side of history and determined to make a difference. It would be a mistake to also suggest it’s not therefore a brilliant bit of acting. Ruffalo feels smaller than usual here, playing a man doggedly fighting a corrupt system that dwarfs him in scale, yet he is also angrier and more empowered at the same time. In a flashier movie, he would have earned awards attention. But a flashier movie would also take away from the earthy beauty of his work. Focus Features Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher 3. You Can Count on Me (2000) Ruffalo’s star-making role, at least in critical circles, was this beautifully small-scale drama of siblings and tiny disappointments. He plays a character that should be insufferable – a damaged, irresponsible man-child endlessly looking to his older sister (Laura Linney) for advice, money and safety. But Ruffalo plays him with such self-loathing and timid naivety that it’s impossible not to want to take care of him, too. Paramount Pictures Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher 2. In the Cut (2003) Jane Campion’s masterful erotic thriller grants Ruffalo the kind of role typically given to femme fatales in these sorts of movies. He is an irresistible enigma here – a cop with a thuggish, seductive presence, whose sexual allure and suave aggression could mask either a troubled soul or a sadistic killer. A notorious flop upon release, In the Cut has only grown in admiration since, partly assisted by Ruffalo’s performance. He is graceful and effortlessly sexy, while simultaneously volatile and threatening. He and co-star Meg Ryan, herself disgracefully maligned back then for having the temerity to be in such a dark and sexual film, create an explosive spark like few others before them. Pathé Mark Ruffalo: His 10 greatest films, from 13 Going on 30 to Foxcatcher 1. The Kids Are All Right (2010) Ruffalo’s character in The Kids Are All Right feels like what would happen if his You Can Count on Me character grew up, grew a beard and went vegan. He plays the anonymous sperm donor to a lesbian couple (Annette Bening and Julianne Moore), who is surprised by the arrival of two children he didn’t know existed. There’s a lovely sleepy energy to his performance here, but also significant trauma. Here’s a character magnetised to screw-ups, someone charming and sweet but perpetually sabotaging his life and relationships. In a film filled with incredibly difficult characters that often stretch the limits of your empathy, Ruffalo is its most haunting and loveable protagonist. It’s no wonder it earned him an Oscar nomination, the Academy finally waking up to Ruffalo’s brilliance, nearly two decades after he started acting. Better late than never. Focus Features

When you consider what Ruffalo himself has been through, it’s no surprise he’s able to plumb such emotional depths. While filming 2001’s The Last Castle, the actor was diagnosed with a brain tumour. It turned out to be benign, but the operation to remove it left one side of his face paralysed for a year (he’s still deaf in his left ear). Then, in December 2008, he suffered the tragic loss of his 39-year-old younger brother, Scott, who was found shot dead in his Beverly Hills apartment. The murder remains unsolved. “I don’t know what I’d be without those experiences,” says Ruffalo. “Something like that happening or any kind of tragedy just opens the world in a different... you realise human beings’ fallibility. I have my own deep insecurity. And so I’m not that certain about anything. None of us know the ending of the story. All of us are walking around with an enormous amount of uncertainty and so maybe I bring that uncertainty to the parts I play. I’m painfully aware of that vulnerability of us as human beings. And in the end we are f***ing toast. No one gets out of here alive, no one gets out of the real struggle and the suffering.”

In the aftermath of his brother’s death, Ruffalo decided a change was needed. Born in Wisconsin to an Italian-American, working-class family in 1967, Ruffalo had moved as a young man to San Diego, California, where he surfed and got stoned before joining the Stella Adler drama school in Los Angeles. Now he parted ways with his agent and publicist, sold his place in LA and moved to upstate New York with his wife, the actor Sunrise Coigney, and their three young children. “Looking back, I think there was a little grief-driven madness in what I did,” Ruffalo told The Sunday Telegraph in 2011. “They say you’re not supposed to make any major decisions while you are grieving but I did the opposite.”

Not what you imagine as a hero: Ruffalo in ‘Dark Waters’ (Focus Features)

He stands by those decisions. “Something like that never really leaves you,” he says. “It’s always there. I find myself being attracted to certain materials based on those relationships and the power of that relationship and that loss. You know,” he continues, “there is a gift in everything tragic if you survive it. You don’t go through that without the person who left you. They leave you a gift that only their passing can give you. That’s the only grace that we have as human beings, that through the suffering we actually gain something that couldn’t be attained any other way.”

After he left LA behind him, Ruffalo’s career began to accelerate. First, he was nominated for a Best Supporting Actor Oscar for his part in The Kids Are All Right, Lisa Cholodenko’s beautifully acted tale of a lesbian couple, and the sperm donor who fathered their children. Then came The Avengers (2012). If the nod from the Academy hoisted him up into the big leagues, then the Marvel franchise made him a star. As Bruce Banner/Hulk, he’s now appeared in five Avengers films and has used his power for good. A fierce supporter of Bernie Sanders, he’s been particularly vocal when it comes to abortion rights. He’s also used his clout to campaign against fracking, and to spearhead a 3 million-strong petition calling on leaders to commit to renewable energy.

Recently, Boris Johnson was in the firing line after he misappropriated the Hulk in an interview, saying he would break off the “manacles” of Europe. “The madder Hulk gets, the stronger Hulk gets,” said the prime minister. Ruffalo replied on Twitter: “Boris Johnson forgets that the Hulk only fights for the good of the whole. Mad and strong can also be dense and destructive. The Hulk works best when he is in unison with a team, and is a disaster when he is alone.”

As a white man, he feels a responsibility to speak about the dearth of women and people of colour in the film industry. “It’s like Joaquin Phoenix was saying at the Baftas, this is systemic and it has to start with us,” he says. I ask if he’s part of the problem. “Yes, we are… actors shouldn’t be flying around in private jets. We don’t have to do that. It’s going to take some sacrifice, we all have to be a little bit uncomfortable… you can no longer think, ‘It’s just about me.’ You have to see that it has impact in all other directions.

‘No other studio is being that inclusive’: Ruffalo alongside Benedict Cumberbatch, Robert Downey Jr and Benedict Wong in ‘Avengers: Infinity War’ (Disney/Marvel)

“So yes, Hollywood, it is systemic, but it’s like asking a fish about water. They’ve been swimming in it their whole lives. This is a hundred years of a certain culture, starting with vilifying Native Americans in film and making them the villains for years and years, moving to black people and villainising them and then a homogenous culture of white supremacy, really. And until we start, consciously as a whole industry, making those changes – that includes actors also saying, ‘Hey, we need diversity on our sets,’ – it’s not going to change. It’s just passing the buck.”

I mention how Marvel has been criticised in the past for its lack of LGBT+ representation. He begins to tell a story. “When we did the first Avengers, [Marvel supremo] Kevin Feige told me, ‘Listen, I might not be here tomorrow.’” He was going to talk to Disney about the issue of why there were no female superhero movies, which they had been discussing while preparing for Thor: Ragnarok. “And he’s like, ‘Ike [Isaac Perlmutter, Disney’s largest shareholder at the time] does not believe that anyone will go to a female-starring superhero movie. So if I am still here tomorrow, you will know that I won that battle.’”

That, says Ruffalo, was the turning point for Marvel. “Because Kevin wanted black superheroes, women superheroes, LGBT superheroes,” he explains. “He changed the whole Marvel universe. We now have a gay superhero on the way, we have black superheroes, we have female superheroes – Scarlett Johansson has her movie coming out, we have Captain Marvel, they are doing She-Hulk next. No other studio is being that inclusive on that level.” He smiles. “They have to, though. This is the f***ing world.”