The singer-songwriter has taken home the award for the first time after being nominated on two occasions.
The 33-year-old’s latest album, titled Kiwanuka, reached number two in the charts after it was released in November 2019 to rave reviews.
Kiwanuka was announced as the winner of the award, which recognises the best British album of the year, live on the BBC’s The One Show.
The Mercury Prize is usually handed out during a concert-style event featuring performances from all 12 nominees.
Kiwanuka, from north London, saw off competition from Stormzy’s Heavy Is The Head and Dua Lipa’s Future Nostalgia.
Laura Marling, Kano, Lanterns On The Lake, Moses Boyd, Porridge Radio, Sports Team, Georgia, Charli XCX and Anna Meredith were also up for the award.
While Kiwanuka’s latest soul-inflected album failed to top the UK charts, his 2016 release Love & Hate was a number one.
Earlier this year Kiwanuka was also nominated in the male solo artist and album categories at the Brit Awards.
On Friday he will appear on a special edition of BBC Two’s Later… With Jools Holland in which he will discuss his creative process and musical influences.
This year’s Mercury Prize was overseen by a panel of judges including Anna Calvi, Annie Mac, Supergrass frontman Gaz Coombes, Jamie Cullum, Jorja Smith and Vice.com’s editorial director Tshepo Mokoena.
Last year’s Mercury Prize was won by rapper Dave for his album Psychodrama.
He beat nominees including Slowthai, The 1975, Little Simz and Foals to the award.
So who is Michael Kiwanuka?
Michael Kiwanuka has enjoyed a meteoric rise since he made the leap from session musician to award-winning solo artist.
However unlike many of his peers, Kiwanuka has not spent years clamouring for the limelight on stage.
Despite getting his first guitar at the age of 12 and experimenting with songwriting during his teens, he has previously said he did not start taking music seriously until the age of 21.
Before striking out on his own with his distinctive soulful sound, 33-year-old Kiwanuka, who is from north London, worked as a session guitarist alongside musicians including grime producer Labrinth.
However he has previously said he realised that “playing guitar for other people wasn’t as much fun as I thought it’d be”.
In 2012, Kiwanuka released his debut album Home Again, which reached number four in the UK album chart and was also named BBC Sound of 2012 winner.
He also featured as a support act for Adele early on in his solo career.
The record won him high-profile fans and Kanye West asked Kiwanuka to join the sessions for his 2013 album Yeezus.
Kiwanuka was asked to sing on West’s track I Am A God but he declined the opportunity as the song was at odds with his Christian faith.
Three years later, Kiwanuka returned with his self-titled third album and earned himself two nominations for the Brit Awards in the male solo artist and album categories.
He missed out on the awards on that occasion but the album has now secured him the 2020 Mercury Prize.