John Mark Ainsley is a leading British tenor especially associated with repertory from the Classical era and earlier. He studied at Oxford, where his teacher was Diane Forlano. In his earliest professional appearances, he established himself as a Mozart tenor, including the role of Idomeneo at the Welsh National Opera and as Don Ottavio at the Aix-en-Provence and Glyndebourne Festivals. His first American appearances were in concerts in New York and Boston, and in 1992 he debuted with the Berlin Philharmonic Orchestra.
His first Viennese appearances were in performances of both the St. Matthew and St John Passions by Bach with the Musik Verein in 1992. The conductor on those occasions was Peter Schreier, who is also one of the era's finest lieder and Bach tenors. Among his other leading roles are the title part of Gluck's Orfeo (his debut role at the Netherlands Opera, 1966), Tito in Mozart's La Clemenza di Tito (for his first appearance in Sydney, 1997), Fenton in Verdi's Falstaff, Lensky in Tchaikovsky's Eugene Onegin, and Jonathan in Nielsen's Saul and David. He has sung and recorded the role of Lysander in Britten's A Midsummer Night's Dream.