Rapper MIKE is three days shy of his 19th birthday and sounding excited about it. That may be because the Jersey-born New Yorker is back living in the UK for a while, where he was once based as a child. But more than that, he's in such a good, anticipatory mood because moving to London has meant he's been reunited with his mother after several years apart. "My mum about to throw some surprise, like dinner for me… I don't know," he says, smiling. "It's supposed to be a surprise, but my mama be talkin a lot." Now his rich baritone voice wraps itself into a deep-chested little chuckle.

He's beaming, and does for most of the time that we sit together in a low-lit restaurant with his 23-year-old manager, Joygill Moriah. We're here to talk about his new video for track "Wait for Me," off his recent By the Water EP. The song, like so much of his work, wields production that twists and turns as though moving through molasses while MIKE's languid flow rides over the top – sample, intimate lyric: "I can't even look in the mirror / I've been lost in my mind". Since first self-releasing mixtapes on Bandcamp two and a half years ago, he's picked up comparisons to MF Doom, Earl Sweatshrt (who's a fan) and King Krule. MIKE sits in his own lane, though, as an open-hearted, thoughtful voice that verbalises many of the anxieties, little joys and ambitions of being a young black man today. Much has been made of how much he's helped his fans, by putting his own mental health struggles into words they can zone out, rap along or bop to. But he's quick to point out that he isn't an island: collaboration and inspiration picked up from his peers have been central to his come-up.

"You ever heard of Standing on the Corner?" he asks, of the jazz-inflected, beautifully experimental band his friends Gio Escobar and Jasper Marsali front in New York. "They talk about something similar to what my 'Wait for Me' video's trying to portray. Their album Red Burns is like … like what some people in the African diaspora see as the devil that can be inside of you." He tells me it all relates to tricknology, a set of beliefs about evil rooted in the Black American political and religious movement, the Nation of Islam. So this sense of a devil you can't shake seeps through the video, he says. In it, "I'm chilling and the devil pops up, and it's like … still a part of me. I feel like it's so human to have that piece of … I wouldn't even call it hate, it's more like depression or anxiety that can sit inside you." Inner demons, I suggest? "Inner demons, exactly, that's what it is. I have these things, and I'm trying to show that I'm letting it be what it is."

It's funny to watch someone speak about something so potentially dark while they maintain such a warm demeanour. Laughter ripples over at least 70 percent of what MIKE says, whether we're talking about what it's like to have picked up press hype, the strength of black single mothers or cutting school. But that's what MIKE is like. He's a natural communicator, which he puts down to having moved so much as a child. From New Jersey, he moved to Hackney and Essex with his mum, before returning to the US to live with his father in Philadelphia until his mid-teens. From there, he went to Brooklyn and the Bronx, while his mother was stuck in Nigeria due to issues with her papers. By 14 he was rapping, by 16 he'd picked up attention from Dev Hynes and since releasing his May God Bless Your Hustle mixtape in June, he's earned more acclaim.

MIKE doesn't use the word relatable, but it doesn't do too badly to sum up part of his appeal. "A lot of it comes from the moving around," he says. "I'm the only boy in the family too, so I'll be empathising with my sisters and trying to understand what they're going through. I'll be putting myself in other people's shoes, to see how they see the world." And so his music has become a constant way to connect him to anyone from South African fans who hit him up online about how May God Bless affected them to the "very blessed black people" in London who've taken him under their wing now. He says he's already working on a new project, which he doesn't get into too much detail on quite yet. First, there's the matter of those birthday celebrations.

Those of you in London can catch MIKE's show at NINES in Peckham on 16 November.