Chiwetel Ejiofor on 'The Martian' and going from slave to scientist

The star of 12 Years a Slave always wants something different, he tells James Mottram

Chiwetel Ejiofor in 'The Martian' with Kristen Wiig

Chiwetel Ejiofor is sitting in a pristine but soulless Mayfair hotel room, staring at the large flat-screen television sitting on the wall opposite. Not switched on, this black slab looks rather like the monolith that appears in 2001. "These are really disturbing to me, these televisions," he muses. "It's an abomination. What are we saying about the modern world?" You suspect this British actor would be happier, sitting by candlelight, reading a copy of Charles Dickens. Still, he has a point: it's an unnerving decoration next to all the mock-Regency furniture.

It's 10am and Ejiofor is diligently undertaking a day's press for Ridley Scott's new sci-fi, The Martian. He arrives, dressed in a maroon jumper, spotless white trainers and navy jeans, and is soon tucking into a cooked breakfast. "We've spoken before, haven't we?" he asks – and he's right, though it was a decade ago, when he played a transvestite in Kinky Boots. Since then, he's worked with Spike Lee (Inside Man) and David Mamet (Redbelt), flirted with blockbusters like Salt and 2012, and – crucially – starred in Steve McQueen's Oscar-winning 12 Years a Slave.

Playing Solomon Northup, the free-born African-American kidnapped and sold into slavery, Ejiofor was marvellous, a pillar of dignity in the face of degradation. The role won him a Bafta for Best Actor and secured him a first Oscar nomination. He eventually lost to Matthew McConaughey, who claimed the statue for his portrayal of a man with Aids in Dallas Buyers Club, but even if he'd won, Ejiofor would probably not be all smiles and high-fives. Triumph doesn't come easily to him. "In those moments, I tend to get reflective as opposed to excited. I don't why that is, but it's always been the case."

Spaced out: Chiwetel Ejiofor (Carlo Allegri/Invision/AP)

After the awards season finished, Ejiofor was done with it all. "Maybe ready for something else and wondering what that something else will be," he says. "Which is life, I guess – you can't really settle on any one concept. You're constantly looking for the next thing." Immediately, he was able to disappear to New Zealand and shoot Z for Zachariah, a post-apocalyptic three-hander co-starring Chris Pine and Margot Robbie. "I loved it," he says. "It was all about discussions, all about craft, all about negotiating cinema, in a very limited context."

If that was the perfect way to decompress after the Oscar race, Ejiofor didn't run and hide. He's soon to be seen as the lead opposite Julia Roberts and Nicole Kidman – "two of the greatest actresses there are" – in the forthcoming remake of the Oscar-winning Argentinian thriller The Secrets in Their Eyes. Then he'll be joining the Marvel Comics universe, co-starring with Benedict Cumberbatch in next year's Doctor Strange (he's playing the super-villain Baron Mordo). It's no surprise that his former co-star Denzel Washington once joked he'd like to have Ejiofor assassinated; he's literally tearing up Hollywood right now.

In the case of The Martian, his second film for Scott after 2007's American Gangster, Ejiofor slips effortlessly into an A-list ensemble that includes Jeff Daniels and Jessica Chastain. Based on the novel by Andy Weir, the story sees Matt Damon's botanist astronaut Mark Watney stranded on Mars, after his colleagues believe him dead. Robinson Crusoe on the Red Planet, this survival story's USP is the depiction of space travel as it really is: slow, methodical, deadly. "It's science fiction meeting science fact," says Ejiofor, who plays Vincent Kapoor, the bespectacled Director of the Mars Mission desperately trying to bring Watney home.

In preparation, Ejiofor hung out with scientists from the European Space Agency, around the time the Philae probe was landing on the Comet 67P last year. "It was very exciting to be around all that energy," he says. In its own way, The Martian is just as thrilling: watching Watney survive not through superhuman powers but using skills even Bear Grylls might envy as he grows food on inhospitable Martian terrain. "What I'm excited about is people seeing this movie, young people especially, and going in [to school] on Monday morning and being like, 'How does this stuff work again?'"

Raised the middle child in Forest Gate, in east London, Ejiofor – known as "Chiwe" to his friends – was never drawn to the sciences at school. While his father was a doctor and his mother a pharmacist in a shop in Brixton, Ejiofor was better suited to the arts. "I remember thinking the miracle of Shakespeare was more impactful than the miracle of science."

There was early tragedy in his life. While his Nigeria-born parents had moved to England after the civil war, the family regularly travelled back there to visit. It was on one such trip, after a wedding, that his father was killed in a road accident. Ejiofor was in the car too, left in a coma for weeks and with scarring on his forehead. "It fucked me up quite a lot in the end," he later said; and it's not hard to see that acting – with its frequent need to explore pain and make sense of the world around you – provided catharsis.

Attending Dulwich College, he started acting in school plays, then went on to the National Youth Theatre, where a casting agent saw him in a production of Othello. Before he knew it, he was screen-testing for Steven Spielberg's Amistad. He uses words like "exhilarating" and "terrifying" as he remembers what it felt like when he won the role of an interpreter. "You've got to go for it. As a performer, you can't walk between the raindrops." When he returned to the stage, in a National Theatre production of Joe Penhall's Blue/Orange, in 2000, he did just that – winning an Olivier nomination for his schizophrenic character.

Since then, his career has been almost exemplary – from sublime home-grown films like Stephen Frears' Dirty Pretty Things (his Nigerian immigrant character inspired by his father) to smart Hollywood choices like Joss Whedon's Serenity. He simply doesn't take gigs for money. "I was always very fortunate to never feel that I had to do anything if I didn't want to. Ever since I started, that was always my attitude, towards being an actor. I would've done something else otherwise. It was always very special to me to do the work that I wanted to do. It seemed pointless to do it if you didn't want to do it. It would be like painting a picture you didn't want to paint."

Still, there are always going to be times when you have to pay the rent, I suggest, and he laughs. "If I was just to do it for money, I'd rather do something else. Acting as an exercise in purely making money doesn't make that much sense." Self-assured, simply that he's doing it for the right reasons, he's just come off several months on stage at the National, in Rufus Norris' production of the 15th-century morality play, Everyman. After stints in Los Angeles – where he was living with Canadian model girlfriend Sari Mercer – he's been enjoying a return to his home city of London. "It's in yer bones!" he laughs.

If Ejiofor has become that all-too-rare thing – a British black actor, plying his trade home and abroad, who has managed to escape casting according to the colour of his skin – he's still well-aware that it applies to others. Last week, he was in an article in Variety about which non-white actor could play James Bond when Daniel Craig leaves. With talk that fellow black British actor Idris Elba was in the frame, this was rather shot down after former 007 Pierce Brosnan claimed of the next Bond, "he'll be male and he'll be white".

If meeting Ejiofor can be frustrating – reserved, wary – you have to acknowledge his ability to handle himself in an interview: he thinks before he speaks.

Certainly, it's hard to see how 38-year-old Ejiofor would deal with becoming more famous. In the wake of 12 Years a Slave, there were paparazzi to cope with, but he kept his life so low-key, they eventually dispersed. While he probably wouldn't take himself to the Red Planet – "my skill set does not include survival on Mars!" he chuckles – he concedes there's an appeal to self-enforced isolation. "I quite like being alone. That chosen sabbatical, the chosen separation from the universe, is thrilling." A chance to escape the modern world and all its flatscreen TVs? He should take it.

'The Martian' is out on Wednesday