Octavian is the first rapper to win the Sound Of… since 50 Cent topped the inaugural list in 2003.
Among the voters was Anna Karatziva, head of talent and music at MTV UK, who called Octavian “a unique and exciting talent with an incredible vision and passion”.
“From the very first moment I heard his music I was hooked,” said Benji B, who was the first DJ to play Octavian on Radio 1 and 1Xtra.
“The first couple of tunes he released – Party Here and Hands – were some of the most futuristic, forward thinking, raw and inspiring tunes to come out of the UK in the last two years.”
However, the star has not had an easy route to fame, spending most of his teenage years homeless after being thrown out of school and, later, his family home.
“A year ago I was poor, I had no money,” he told the BBC.
“But I was never depressed. I was never in the mode to give up. Around me it was bad, but I kept motivated.”
On winning the Sound of 2019, he added: “If I can get this, I can get anything. 2019 is going to be a great year.”