"I'm ambitious… I'm overly ambitious," Idris Elba admits coolly. Looking at his somewhat meteoric career, this much is evident.

He's played leading central characters in cult hits such as The Wire and Luther (for which he earned a Golden Globe), he's starred in Marvel's Avengers blockbuster series, he recently lent his voice to the part of the fearsome Shere Khan in the remake of Disney classic The Jungle Book, and next year he'll be starring alongside Matthew McConaughey in an adaptation of Stephen King's The Dark Tower, to name but a few of his roles.

As impressive as this list of achievements reads, there's a whole load more strings to Elba's bow: he's spun the decks at Glastonbury and several leading London and Ibiza clubs (a passion which began while he was a teenager, when he started working as a DJ on a pirate radio station); he's designed a slick, graphic collection with fashion giant Superdry; he's championed the work of the Prince's Trust, working with the charity to produce a promotional documentary on its work; he's spoken out on the lack of diversity in his industry; and he's due to direct a feature film within the year as well.

"I just don't want to put the kibosh on going for things that interest me. Whether that's acting, whether that's music, whether it's being a teacher at some point, I don't know. I don't want to say I'm never going to do something," he says. This broad range of interests doesn't make him unique – the actor/musician/fashion muse mould isn't a new one, after all – but few have gone for it with the same relentless energy, or personality.

That's the thing: ambitious Elba may be, but he wears that quality – which can, in others, be less than admirable – with charisma, and he works hard at everything he turns his hand to, frequently going for more than 24 hours without sleep. The question arises if there's an end goal in mind? "I don't think there is anything specific I want to achieve," he muses. "My ambition is to be happy... I think it's a continual thing."

With someone so obviously driven, there's always an element of curiosity about where it comes from. "About 70% of it is me pushing and pushing and wanting, and also my mum and dad telling me that it's good to work, and encouraging me to be independent. I think they were worried I'd be influenced by a bunch of no-gooders."

I don't think there is anything specific I want to achieve. My ambition is to be happy...

Given Elba's determined nature, that might seem unlikely, but things didn't always look so rosy. He spent his early twenties in New York, knocking on doors that weren't opening. "That was my lowest point, living in New York after three or four years of not getting much work and realising that, with a baby on the way, I wasn't going to be able to stay."

Talking about the desperation of the situation is where Elba's strength of character shines through. "I dug my heels right in and said I won't take no for an answer," he says. "What got me through was this no-fear attitude I have. It made me work harder, audition harder and be more proactive as an actor."

Idris Elba Square Mile interview

It's no surprise that, stardom achieved, he's outspoken on diversity issues. Part of the reason why he moved to New York in the first place was because he saw a ceiling for black actors in the UK: "I recently spoke up on diversity in my industry, which is an important one for me and it's relatable to me. My industry definitely needs to talk about diversity more." That said, when it comes to the recent criticism over the lack of diversity of the Oscars, Elba is dismissive: "I think we're losing the plot a little bit if we're worried about the awards season being diverse. It's a bit backwards, surely? We should have an industry that encourages diversity and perhaps then the awards might reflect that."

Yet Elba is also very selective about what he chooses to endorse – "I tend not to lend my name too many times to things that I do not necessarily actually believe in personally or can affect."

What's most refreshing is his way of tackling these issues: "I tend to use my art if I can – like making Beasts of No Nation, about child soldiers, or Sometimes in April, which is about Rwanda – to make more of an impactful message and get people to think about things."

He's more than shown how effective this can be, taking on the role of a fatherly but ruthless African warlord who brings together a gun-wielding army of young boys for Netflix's first foray into feature films in Beasts of No Nation – a performance for which he was awarded the Screen Actor's Guild award for Best Male in a Supporting Role, and which drew attention to the plight of child soldiers.

The most recent project Elba has chosen to bring his considerable influence to is drinks brand Purdey's Thrive On campaign, for which he'll be encouraging people to follow their own ambitions. "I've been meeting a lot of people and asking them what they want to do outside of their regular job – asking them what they want to be when they grow up. They're in regular jobs, but they've always dreamed of something that from their perspective is completely unattainable. So I'm directing a series of films with real people that have come to me. I've chosen a bunch of people and gone right, you want to be a football trainer, I'm going to help you get your licenses."

No. I don't think I'd ever be tempted to pursue a career in the City. My maths is terrible!

This is a precursor to his next move: "I love to direct, it's a natural course for an actor but I particularly love it." Elba's first feature film is, in fact, in development, with hopes that it'll come into being early next year. His chosen subject is a nod to his London roots, based on the book, Yardie, and focuses on the story of a group of violent Jamaican gangsters of the same name who built up a drug empire in London during the 1970s.

The gang's strongholds were Brixton, Harlesden, Tottenham and Elba's native Hackney – areas which are now at the forefront of London's path to gentrification. Stories like that of the Yardies are all part of the capital's cultural heritage, which some people fear is being lost. "There are instances in London, and all over England, where rejuvenation has ripped the heart and soul out of that city and that town and that saddens me. But Hackney thankfully isn't one of those."

Despite living in the States, he's still very much in touch with his hometown – especially when it comes to another of his interests: football, and more specifically Arsenal. "I think Wenger's been solid. It's called football, it's not called winning. You want us to win, we want to win, but I think he's done a good job to make a great team." Still, something suggests that, if Elba were in charge, he wouldn't have accepted second best this season.

But would he ever apply his zeal to a career in the City? "No. My maths is terrible!"

Thrive On is a partnership between Purdey’s and Idris Elba, a platform designed to enable and inspire people, giving them the courage to follow their own path. facebook.com/Purdeys