Hughes was born in Ton Pentre, Rhondda, the son of another successful musician, composer Arwel Hughes. He studied at Howardian High School, Cardiff, University College, Cardiff and the Royal College of Music. He studied conducting under Sir Adrian Boult, Bernard Haitink and Rudolf Kempe.
He became well known after a rousing televised performance of William Walton's Belshazzar’s Feast, which won the praise of the composer himself. He later hosted a BBC series, The Much-Loved Music Show. He has also made numerous recordings, including works such as Verdi's Requiem and Handel's Messiah. He has championed less well-known composers, including recording a complete cycle of the symphonies of the Danish composer Vagn Holmboe. In 1982, he conducted the first performance of Turandot by Puccini, with the original Alfano ending, at The Barbican Centre in London.
Hughes has been the Chairman of Governors at the John Lyon School, Harrow. Hughes has been married to his wife Jean for over forty years. His son Geraint Hughes is a former sports correspondent for BBC News and currently works for Sky Sports.
Hughes's former and current appointments include:
- Philharmonia Orchestra, London, Associate Conductor
- Royal Philharmonic Orchestra, London, Principal Associate Conductor
- BBC Welsh Orchestra (now the BBC National Orchestra of Wales), Associate Conductor (1980–1986)
- Aalborg Symphony Orchestra, Denmark, Principal Conductor (1994–1999)
- Cape Town Philharmonic Orchestra, South Africa, Principal Guest Conductor
- National Youth Orchestra of Wales, Musical Director (2003–2010)
- Huddersfield Choral Society, Director
- Camerata Wales, Founder and Musical Director (2005–)
- Welsh Proms, Founder and Artistic Director (1986–)
- University of Wales, Trinity Saint David, Professor of Performance (1986–)
- Hughes, Owain Arwel (2012). Owain Arwel Hughes: My Life in Music. University of Wales Press. ISBN 9780708325308. Autobiography