Twizzle - real name Bradley Bellot - served six months in Feltham Young Offender Institution when he was 16. Now he wants to use his experience to turn youths away from crime.
The 20-year-old grew up in White City with his mother and began writing lyrics aged 13. But he fell in with the wrong crowd and turned to crime to buy "nice things".
He said: "My mum always worked hard, but I've never liked relying on people. I also did it because I wanted to be the man.
"I started selling marijuana, and moved on to harder drugs. When I went to jail it hit me. I thought, I just don't want to do this I came out wanting to make music seriously."
Twizzle funded and recorded his own single, which was picked up by music channel MTV Base.
He has just signed a publishing deal with Warner Chappell, a subsidiary of Warner Music Group, and is about to release his debut mix tape The End Is Near.
He added: "I just wanted to prove that people can change. I don't want to see these kids making the same mistakes I did." Twizzle is appearing in the Dec-ember Sessions at The O2 tomorrow.