Martin James Bartlett, from Essex, won the BBC Young Musician honour with his performance of a Rachmaninov piece.
The contest, which is held biannually, returned to the capital’s flagship concert hall exactly 10 years after Ayrshire violinist Nicola Benedetti’s triumph as a 16-year-old in the same venue, which is currently celebrating its 100th anniversary.
Bartlett, who began learning the piano at the age of six is already studying at the Royal College of Music in London, won huge acclaim from the Usher Hall audience for his performance of “Rhapsody on a Theme of Paginini.”
He said: “I can’t believe it - it’s such an amazing feeling.
“I’ve always just dreamt of just being in this competition and I can’t believe I’ve just won it.”
Bartlett edged out 15-year-old recorder player Sophie Westbrook and percussionist Elliot Gaston-Ross, also 15, who deployed two dustbins and a wheelbarrow for part of his performance.
All three performers were accompanied by the BBC Scottish Symphony Orchestra, with the entire concert broadcast on BBC Four and BBC Radio 3.
More than 450 musicians from across the UK entered the competition and the three finalists won through after four intense rounds. Bartlett’s title comes with a £3000 cash prize.
Tony Hall, the BBC’s director general, said: “I’m delighted we’ve been able to bring this very special event back to the Usher Hall in the venue’s 100th anniversary year.
“BBC Young Musician is something that we’re very proud of at the BBC and 36 years after the competition was first held, it continues to hold a very special place at the heart of the cultural life of the UK.”