He was awarded the CBE (Commander of the Order of the British Empire) in the 2015 Queen's Birthday Honours List for his services to Music. He is the Choral Conductor in Warwick, Warwickshire, England.
His father, Louis Halsey, founded several choirs in the UK. At age 8, Simon became a boy chorister at New College, Oxford, and later at King's College, Cambridge. He studied conducting at the Royal College of Music in London.
He has led the City of Birmingham Symphony Orchestra Chorus, the Netherlands Radio Choir, the Berlin Radio Choir, and the London Symphony Orchestra's chorus.