Damian Lewis has been hanging around a lot of billionaires lately. And not just hanging around with them, but trying to get into their psyches, analyse their lifestyles, investigate what makes them tick.

The fascination is not completely one-sided. The mega-wealthy like to approach him at parties, shake his hand, tell him what a great job he’s done of portraying them.

Which is perhaps as telling an indication as any that Lewis – a British-born, Eton-educated actor who shot to prominence playing a second world war US Army officer in the TV mini-series Band of Brothers – is also profoundly successful in his role as a hyper-confident and in-control New York gazillionaire in the series Billions. Now in its second season, Billions is about Bobby “Axe” Axelrod (Lewis), a pathologically competitive hedge-fund manager who, although philanthropic and loyal, is also somewhat Machiavellian in his methods of boosting his already gargantuan fortune (i.e., insider trading and bribing people). The hit show also stars Malin Åkerman as his wife Lara and Paul Giamatti as Charles Rhoades Jr, a US attorney who is out to entrap Axelrod.

Lewis, one of the most consistently exceptional actors working in Hollywood today, brings a multitude of layers to his part. While many of his character’s actions are reprehensible, he remains a likeable fellow. When the pilot opens, he’s stepping in to help save the beloved pizza parlour from his childhood. In the next scene, he’s scheming to swoop in on some unethical transaction. In the entertainment industry, Lewis is known for that chameleonic gift, whether as an imposing Henry VIII in the award-winning Wolf Hall, or as the tortured and treasonous Nick Brody in Showtime. On a recent afternoon in Pasedena, the actor reflected on the world of Billions.

What have your experiences been with hedge-fund types?

Every hedge-fund billionaire I meet thinks that Bobby Axelrod is him. I don’t know how closely they’re watching the show, because I don’t think they would want to own up to that, given some of the things that Bobby does. But I’ve had either billionaires or their employees saying, “It’s so incredible that you’re playing my boss.”

Did you create Bobby based on these people?

I started off wanting to borrow heavily from the people that I had met. I found them all to be very good listeners, very watchful. But they don’t consider themselves to be gamblers. They consider themselves to be in a post-Gordon Gekko, post-asset-stripping world. They consider themselves to be activists for good. There’s a certain zeal in what they do. They consider themselves to be scientific and extremely analytical and they like to present themselves that way. But of course, there is great vanity. What drives them is the game. None of them are billionaires to start with.

It’s all to do with professional, personal pride, status, vanity, ego. In the end, it’s bragging rights.

What were some of the surprising things you discovered after mixing with real-life billionaires?

I met billionaires who were happy to be in sweats and sneakers, and went to work like that. I met other guys in US$4,000 Tom Ford suits and $500 haircuts. And actually I had to adjust quite a lot at the beginning of season one, because I had not fully grasped the kind of show that the writers were writing.

I’ve found Bobby to be a far more swaggering, athletic, prowling, sort of blue-collar alley cat than any of the people that I met. And once I settled on that, I really went to town with that. I used that physicality. I use [some traits of] animals a lot when I am acting. I like the anthropomorphic sort of shift between humans and animals.

What’s the key to making Bobby likeable? And what did you learn from hanging out with the billionaires that helped achieve that?

These people are our leaders, they galvanise communities, are compelling, have made a lot of money – they might even be in political power. They’re all borderline or fully fledged sociopaths. They are able successfully to compartmentalise their emotional lives, which is why they can act without shame or guilt. If you’re the leader of the free world, you need to be able to compartmentalise because you’re going to have to make tough decisions. I don’t see anything wrong with sociopathy – it’s just a mechanism.

The trick is to make them likeable, otherwise we lose viewers. In the end, people won’t watch things for a long time where nobody is likeable. These are larger-than-life characters and everything they do is with such relish. It’s written with relish and we’re encouraged to perform it with relish. That way I think people will continue to watch and enjoy these characters.

The show also has a particularly newsy feel.

I think that’s one of the reasons this show is timely. There’s a contradiction in what’s going on at the moment. We’ve got a billionaire – or is he? – running the free world. He seems mostly not to be liked, but liked enough to be voted in. But in spite of what he says, the people who voted for him, who claim not to be racist or bigoted, were happy to vote him in because they appreciate his success. He seems to have sold them the story that, “I was a successful businessman and I can turn your communities around, applying my business model to government.”

I think there’s a greater suspicion about billionaires and about wealth and accumulation of wealth. People are asking for the first time, “Excuse me, how did you become a billionaire exactly, because I just lost my house?” So I think it’s an interesting transitional point. Having said that, I think there will always remain a certain rock ’n’ roll element to the guy with the money and the fast car.

There was a time in TV when the leads in so many shows were women. Now we’re back to leads being disproportionately men. What do you think of that?

I think feminism was in a particular place in the 1980s. I won’t pretend to be an expert on it, but women were being enfranchised in a way they never had been. They were starting to take executive positions in the workplace in the way that they never had before. There was an anger in feminism in the ’80s represented by people like [women’s rights activist] Andrea Dworkin. And Margaret Thatcher was a visible and formidable leader of a leading nation. So, that was a natural time to have women emerge in these leading roles. And if you feel they’ve gone away, then they shouldn’t have and I don’t know why they have.

But certainly what [Billions co-stars] Maggie Siff and Malin Åkerman have been keen to point out, and I think the writers have been keen to write, is that they are not just appendages to myself and Paul. They are anything but.