Tyrone Lindo - aka Big Narstie - has gone from selling drugs after school at age 13 to forging a terrific career as a grime artist and TV personality with a talent for comedy, collaborating with Ed Sheeran, Craig David and Robbie Williams, among others.
The "King of Base" has also crossed humorous swords on his Bafta-nominated eponymous Channel 4 chat show with the likes of Stephen Fry, David Mitchell and others with more privileged backgrounds, but Narstie gives as good as he gets - and viewers love him for it.
Yet, the 34-year-old rapper knows he could so easily have faced the same fate as his Brixton schoolmates, who he says are serving long jail sentences, or are dead.
Now, the grime artist once destined for a life of crime has written his first book, How To Be Narstie, a part-memoir, part-guide to life, including a foreword by his friend Ed Sheeran, who is godfather to one of Narstie's two children.
Sheeran writes: "Over the last nine years of knowing him, he's never minced his words and is brutally honest with me in his opinions; no beating around the bush, just straight to the point."
The same can be said of the book. It's really funny in places, but behind the humour it's clear his life has been tough and violent. It was hard to return to those memories when writing, reflects Narstie, who has bipolar disorder.
"When you get to a certain stage in your life, you want to put it behind you," he says, devouring a burger as he talks.
His mother, to whom he remains close, was an NHS nurse. His father, who died three years ago, ran clubs in the West End and would take his young son along. He'd whip him with a weightlifting belt if he misbehaved.
"I was scared of him sometimes and it's affected the way I bring my own children up," he says. "I said to myself, 'That cycle isn't going to be passed on to the generation at the end'. It was his story, not mine.
"I'm a trying dad (he means a dad who tries). I'd never been a dad before. Five years ago, all I cared about was myself.
"Every day's a learning curve, but as long as you're 100% trying what you do, working at it trial and error, and taking a bit of advice, that's what I do."
His Jamaican parents split up when he was six and Narstie didn't have any contact with his father throughout his teenage years. This was the point, he says, when he lived the life of a "barbarian", selling drugs, getting into fights, stealing and terrorising richer kids. He was caught up in a culture of violence.
"The exposure to violence made me very numb to it," he explains.
"It becomes normal. If you're taught that when someone upsets you, the first thing you should do is to hit them and that any situation can be handled with brute force, you just become a record playing that story to all your friends."
He notes in the book that he saw one man get his head blown off - he won't elaborate - and, on another occasion, Narstie himself narrowly dodged bullets.
His older brother ended up in prison when Narstie was in his teens - he still visits him and says they have a good relationship. But his mother urged her younger son to get out of Brixton, fearful he would go the same way.
Ironically, being sent to a detention centre after a fight was his saving grace, he reflects.
It was here he was introduced to the 409 Project in Brixton, a charity working with teens at risk of offending. He also got help from the pastor at his local church youth club.
His career started as a rave MC, first playing local youth clubs and house parties, finding fame as a rapper, first as part of the grime crew N-Double-A, and later as a solo artist.
Collaborations with Craig David (When The Bassline Drops) and Ed Sheeran (who has a rap verse on Narstie's album BDL Bipolar) followed, as his TV career took off on the back of an appearance with Sheeran on Celebrity Gogglebox, which went viral.
Since then, he has appeared on Would I Lie To You and Bake Off, and has even presented the weather on Good Morning Britain. His chat show has just completed its third series.
His star is still on the rise and he'd love to collaborate with Adele - "Her voice is awesome" - and Arctic Monkeys.
The biggest question is, how did he escape that path of crime when so many of his peers didn't?
"Honestly, it was pot luck," he says. But when independent record label Dice Recordings took a chance on signing him, that sparked his move from Brixton.
"The first thing, before they could even think about my musical and entertainment skills, was that I'd have to change my environment, where I'm living.
"I would have been no good to a record label or television company in the trenches."
Today, he lives in Essex with his partner, whom he met when she was DJ'ing at a youth centre in Brixton, and their two young daughters. He has no intention of thrusting his family into the limelight via social media, he says.
"I signed up to be famous, they didn't," he asserts. "I want them to have as normal a life as possible. My four-year-old daughter doesn't know who Big Narstie is. She just knows daddy."
Fatherhood has changed him, he adds.
"Having children has changed me in every way. I'm responsible for life. I've made two lovely human beings and how I treat them and raise them will show if they want to be a benefit to society, or a nightmare to society."
While his profile has been raised through his chat show, co-presented by comedian Mo Gilligan, it took him a while to get used to meeting celebrities.
"It felt very surreal, a sort of pinch yourself moment. When I had Ross on from Friends (David Schwimmer), they warned me about a million times not to call him Ross. As soon as I walked out, I said, 'Hey, Ross!' I'd grown up with him my whole life."
He says he doesn't care about fame or what the media says about him.
"There's no headline that could ever put me through more trauma than I've experienced in real life," he writes.
Indeed, the book is full of pretty scary anecdotes. On one occasion, he damaged his hand so badly after being attacked by a "crackhead" that the wound turned gangrenous.
What are his goals today?
"Music will always be the big one for me," he says. "It's my first passion."
How To Be Narstie by Big Narstie is published by Ebury, priced £14.99