Under the name of John Hahessy ( his father was from Carrick-on-Suir, Co.Waterford, Ireland ) he had considerable success as a boy soprano - from BBC broadcasts and recordings with Decca to concerts with such conductors as Benjamin Britten.
He went on to study at the Royal College of Music, and made his stage debut as a tenor in 1968 at The Proms.
His repertoire is extensive ranging from Monteverdi, Charpentier, Rameau, Bach and Handel to Mozart, Schubert, Schumann, Mahler and Britten.
He regularly performs with the leading conductors of baroque, classical and contemporary music.
He has sung in over one hundred recordings, including Dowland's First Book of Ayres, Schubert's song cycles Die Schöne Müllerin and Winterreise, Purcell's The Tempest, Bach's St Matthew Passion and Mass in B minor, Handel's Messiah and Mahler's Das Lied von der Erde, for which he was nominated for a Grammy Award in 2008.