Patrick Neate has beaten Ian McEwan to the Whitbread Novel Award with his second book, Twelve Bar Blues.
He now goes forward to the overall Whitbread Book Of The Year title later this month with the winners of four other categories.
Neate's tale was described as "vivid, bold and energetic" by prize judges.
The author, a part-time DJ, has written extensively about black music for magazines such as The Face and Q. He is also working on the screenplay to the Alex Garland novel The Tesseract.
Twelve Bar Blues is an epic tale set against the world of New Orleans jazz early in the last century as musician Lick Holden searches for his step-sister.
Judges added: "The electrifying prose brings to life characters whose experiences span one century, several cultures and many colours."
Neate has previously won acclaim for his novel Musungu Jim And The Great Chief Tuloko.
McEwan - a previous Whitbread Novel Award winner in 1987 with A Child In Time - had been in the running for his Booker-shortlisted Atonement.
Two other novelists were also up for the prize, Helen Dunmore with The Siege and Andrew Miller's Oxygen.
Neate, who is 31 and lives in Hammersmith, west London, wins £5,000 for his triumph, as do three other Whitbread prize-winners who were announced today.
Sid Smith landed the First Novel Award for Something Like A House, while the Poetry Award went to Selima Hill for her collection Bunny. The Biography Award went to Diana Souhami for Selkirk's Island.