When he's not gracing the screen, the star of films like The Social Network and Zombieland prefers to hide away in remote locations.
"I just got back from Cambodia. I camped there for pleasure. It's interesting to go to unique places," he reveals.
The more unusual and weird a location is, the more appealing he finds it.
"I went to Nepal during a civil war; it kind of broke out while I was in China," he continues. "I went into Tibet, then to Nepal, and it was really dangerous at the time."
Much like some of the characters he's portrayed, the 30-year-old, looking casual today in a T-shirt, jeans and Nike trainers, speaks quickly, eager to deflect attention from himself. He's very inquisitive, and bounces questions straight back.
Eisenberg is in the UK to promote his new film, the thought-provoking drama Night Moves. Unlike his real-life self, where he often fidgets and doesn't really maintain direct eye contact, his performance as radical environmental activist Josh is probably his most intense yet.
"It was interesting. I mean, I'm not locked into one kind of acting so I liked doing it," he says of the challenge. Josh feels a lot of pain and anger but doesn't know how to express himself, so he ends up repressing all of these feelings."
The New York-born actor was intrigued when he was sent the script by film-maker Kelly Reichardt.
"I like the character," he says. "The fact that the movie raises these kinds of interesting issues is more for the audience to enjoy, but for me, the most interesting thing about this role was this guy who is very passionate about something. He knows that to satisfy this passion is to do something very dangerous."
"I can relate to feeling so interested in something that you end up doing things that you would later regret," he continues. "When I put on one of my plays, it took me a year to write it. I was so focused that I probably ended up alienating friends and family. I can understand taking it to a much greater extreme."
To prepare for the part and get into Josh's head, Eisenberg stayed in a yurt.
"I lived in a yurt for less than two weeks, because my character lives in a yurt and I wanted to see what that was like," he says. "It was very interesting. I had a better understanding of the pace of my character's life. You don't have cellphone reception, so naturally, you become more internal and isolated, and there's no electricity, so you live more simply."
The self-confessed cat lover has carved out a name for himself, jumping from indie movies like The Squid And The Whale and Woody Allen's To Rome With Love, to bigger studio fare like David Fincher's The Social Network, animated hit Rio (he voices Blu) and Now You See Me.
But his biggest role to date will be playing Lex Luthor in Zack Snyder's Man Of Steel sequel, Batman v Superman: Dawn Of Justice, opposite Henry Cavill as Superman and Ben Affleck as Batman.
"The character is, luckily, a really great character. Actors can sometimes find really cool things in characters that aren't written well. This character is written really well," he says.
Aside from films, Eisenberg - who started acting when he was 10-years-old - has written and performed in plays. He also pens pieces for The New Yorker magazine.
But the stage and big screen are his first loves. His plays tend to focus on interactions between an American character (normally played by him) with a foreigner, linked in with his exotic travels.
"I'd love to do more theatre. It's very hard for me to break into the world of playwriting; it took me many years, so now that I have done it, I want to continue."
Yet he admits performing is a "form of torture".
"Every performer I know tortures themselves for it. On a movie set, you're using your real emotions in very difficult ways, so you end up feeling bad. But the tortured ones tend to be more interesting roles," he explains.
His proudest role to date though is playing two characters - a man and his doppelganger - in The Double, co-starring Mia Wasikowska, whom he is now dating.
"I just loved doing it. That's an opportunity I'll never get again, to play two roles in the same story," he says.
With strong roles on the horizon and an actress girlfriend, he is firmly settling into his skin. But don't expect him to Google himself any time soon.
"My dad always tells me, 'Any actor who Googles himself should be arrested', because it's an upsetting thing. The only time I would be in touch with people's perceptions of me is when I'm doing interviews," he says. "Acting is such a weird profession."