Sampha has won the Mercury Prize for his album which ruminates about the loss of his mother from cancer.
The soul singer from Morden, South London, won the award for the album Precious which also depicts his own fears for his health.
The presenter Lauren Laverne described the process of choosing the winner as the "longest deliberation from our judges ever".
In his speech, he said: "I feel like I'm dreaming!" and thanked his parents for giving him and his family "the best upbringing possible."
He was born Sampha Sissay in London to Sierra Leonean parents and emerged on social media a decade ago where he was discovered by music producers impressed with his voice.
He has sung on records by other artists such as SBTRKT and Jessie Ware and has also featured on Beyonce's Mine, Drake's Too Much and Solange's Don't Touch My Hair.
Of his own record, he told the BBC: "It's taken me quite a while to feel like I was emotionally stable to write my own record and people have been incredibly lovely and understanding."
The 28-year-old was up against the rapper Kate Tempest who was one of the bookies' favourites, as well as grime artist Stormzy, the rock group Blossom and former nominees the XX.
A sign of the award shifting to the mainstream was the nomination of chart-topper Ed Sheeran, who was the only nominee not to perform on the night at the Eventim Apollo in Hammersmith, west London.
In recent years, the award has been given to artists who may have not enjoyed much commercial success. Kate Tempest's album Let Them Eat Chaos had been the favourite to win, although it was always a close contest between her, Sampha and art-rock band Glass Animals, the BBC reported.