Jesse Eisenberg - The young star with the status update

It's a winter's evening at London's Charlotte Street Hotel. The bar is buzzing, though chances are most patrons have failed to notice Jesse Eisenberg. Never mind that his face has been on posters everywhere for David Fincher's The Social Network (currently at $209m in global box-office and, following its Best Picture win at the Golden Globes, a hot favourite this awards season).

When he does get spotted, most tend to think he's Scott Pilgrim star Michael Cera anyway. "People recognise me all the time as him," he says. "It's annoying. I don't like getting recognised as other people."

We retire to the library, Eisenberg nursing the remains of a mojito. Dressed in a nondescript navy shirt, grey slacks and battered trainers, in the past three months he's been "to all the rich countries", obediently banging the drum for the film in which he plays Facebook founder Mark Zuckerberg. Now, with a first Oscar nomination safely in his pocket, he's back here for a Bafta screening of the film. Up for Best Actor in the awards that take place in London on 13 February, he's obviously hoping to persuade voters to plump for him instead of Colin Firth.

Eisenberg is a little bamboozled by it all. "I've never been involved in a movie that's received this kind of attention. I've never played a role that's received this kind of attention." Indeed, many of his films – even such critically respected efforts as Roger Dodger, The Squid and the Whale and Adventureland – have fallen through the cracks.

Yet this is different, the film inspiring discussion "about communication and technology", as Eisenberg neatly terms it. In the wake of the film's release, Time magazine aptly named the media-shy Zuckerberg their Person of the Year "for changing how we live our lives" after the social networking site registered 500 million users.

It's easy to see why Eisenberg was cast as Zuckerberg, beyond the fact they share certain physical similarities (tight curls of light brown hair, pale skin, inquisitive eyes). The best of his early roles were articulate yet awkward teenagers struggling to fit in, and his take on Zuckerberg is an extension of this.

"He's somebody who feels like he's on the periphery of social interactions," says the actor, "and to cope, he creates an incredible tool to interact." While his cousin Eric works for Facebook, Eisenberg only met Zuckerberg for the first time last weekend – when he and the face behind Facebook turned up on a skit on Saturday Night Live, an experience he called "overwhelming".

As with Zuckerberg, The Social Network has thrown the 27-year-old into the spotlight. He has already won Best Actor for the National Board of Review and with Screen Actors Guild, Bafta, Golden Globe and Oscar nominations too, it's been a real head-spin.

"I imagine this will be the only time in my life where this will happen," he says. Yet "the endless promotion" has "been a bit jarring", particularly when it comes to fronting an awards campaign. "There are actually some people who do this every year," he sighs. "To me it just seems like a really taxing process. You lose a sense of perspective. You lose a sense of needing to be creative. You lose a sense of what actual life is like. And you lose a sense of your own abilities."

Not to mention that fact it's all making him feel a little suspicious. "The more people say nice things about me, the more I feel it's false. Or the more I look for the things that are bad about me, and think those are the real ones. I could overhear somebody say something about me, and it destroys me for a week. Yet I could win an award or hear nice reviews and it feels meaningless." Take the National Board of Review prize: "It was great. But then I immediately found some reason to be miserable again that night. It's terrible. I'm able to manipulate things into being bad, which is not a healthy way to live but that's where I'm at now."

This is a typical Eisenberg statement, a mixture of mild self-loathing and sharp self-awareness. Full of East Coast angst, as he sits hunched on the sofa in front of me it's no surprise to learn that he's in analysis. At one point, he tells me that, while he hates watching his films – a fairly common response by many actors – "my therapist says that I should because you have to treat it with more respect". He studied anthropology at college and spends his spare time writing plays and prose, and even penned a musical, Me Time. Should anyone ever make a film about Woody Allen, Eisenberg would be a frontrunner for the role.

Still, he's not a pain to be around. He has a wonderfully wry sense of humour, not least when I ask him if his new-found fame has seen him get mobbed in the street. "Mostly grandmothers on the Upper West Side," he grins. "They want to spread their lipstick on my cheek." His New Jersey upbringing was middle-class, safe and comfortable. His father Barry is now a sociology professor and "has an appreciation for the arts" – though Eisenberg can remember telling him that his "main goal" was to be in the ensemble cast of Les Misérables. "He was like, 'Please don't do that! Why would you want to do that?' He's not right, of course."

Fortunately, his mother Amy was a professional clown for 25 years, entertaining birthday parties in Queens. "It was great ammo to use in my defence of my chosen profession," he says. He started acting when he was nine, in community theatre, and later went to a performing arts school, where he got called to do an early reading for the script of Roger Dodger. So good was he – playing the naive nephew to Campbell Scott's self-professed ladykiller – that the producers earmarked him for the role. "I got so lucky. It never, ever happens. It was the strangest thing. I would not be an actor otherwise, because it's impossible to get movie parts. It's impossible!"

He's not the only actor in his family, however. Of his two sisters, Hallie Kate – who has just turned 18 – was on screen even before he was (not least playing Russell Crowe's daughter in The Insider). She's also in Holy Rollers, one of Eisenberg's new films, playing his sister. "She did me a favour," he laughs, "because I assured her that none of her friends would ever see the movie." Another true story, like The Social Network, it's a late-Nineties set story of Hasidic Jews who fall in with a bunch of Israeli gangsters and start smuggling in ecstasy from Amsterdam. "The character I play didn't know it was drugs," he explains. "He thought it was medicine. That's what was told to these kids."

As Sam Gold, the son of a Brooklyn fabric-store owner, it's another coming-of-age role – what might seem like a step backwards after The Social Network. But then Eisenberg – whose own family has Jewish roots in Poland – is not really cut out to play the alpha male. He may have shotgunned a few of the living dead in the 2009 action movie Zombieland (one of his very few concessions to mainstream Hollywood) but even there he played a shy college student. And in the forthcoming computer-animated film Rio, he voices a "nerdy and cowardly" macaw that lives in a Minnesota bookstore.

He says there has been no change in the type of scripts he has been receiving since The Social Network was released – perhaps because he's so identifiable with Zuckerberg and his ilk. Eisenberg may not be worth $25bn ("I'm so naive when it comes to business stuff") but he's from the same generation. He even started his own website, oneupme.com, three years ago. An online wordplay game, in which users try and out-do each other, nothing happened initially. Now his cousin runs it, through Facebook. "It's the final nail in the irony coffin," he says. "It's finally successful because of Facebook. In the same way I'm in a popular movie because of Facebook."

Understandably, given his rising celebrity, Eisenberg doesn't hold a Facebook account. Yet his internet stock seems to be growing with a rising number of fan-sites dedicated to him. Though I know that he's lived with his girlfriend, Anna – who is six years his senior – for four years, I tease him a little, asking if the film has gained him more female attention.

"No, not at all," he replies, earnestly. "I have been working so much. I imagine there are people who, when they become part of a popular movie, find themselves meeting a lot of new people. But that hasn't been the case with me."

The way Eisenberg sees it, all the current hoopla around him will soon be at an end – "and one day, I can tell my children about how silly it was". So will he simply go back to playing nerds? He has just finished shooting the kidnap comedy 30 Minutes or Less, in which he plays a pizza delivery guy, so perhaps he will. Curiously enough, he says that his co-star Danny McBride – who regularly plays rednecks – "captures the perfect American archetype". But as the very embodiment of the digital-age entrepreneur, in a way, so does Eisenberg.

'The Social Network' is available to buy on DVD and Blu-Ray from 14 February. 'Rio' opens on 8 April. 'Holy Rollers' will be released later in the year