Nicholas Isherwood is one of the leading singers of early music and contemporary music in the world today. He has worked with conductors such as Joel Cohen, William Christie, Peter Eötvös, Paul McCreesh, Nicholas McGegan, Kent Nagano, Zubin Mehta and Gennadi Rozhdestvensky and composers Sylvano Bussotti, Elliott Carter, George Crumb, Hans Werner Henze, Mauricio Kagel, György Kurtág, Olivier Messiaen, Giacinto Scelsi, Karlheinz Stockhausen and Iannis Xenakis in prestigious venues around the world, such as La Scala, La Fenice, Covent Garden, the Théatre des Champs Elysées, Salzburg Festival, Concertgebouw, Alte Oper Frankfurt, Vienna Konzerthaus, Ravinia, Tanglewood.

Some highlights of his operatic career include the role of Plutone in Monteverdi's Il Ballo delle Ingrate at the Angers Opera and Antinoo in Il Ritorno di Ulisse in Patria and Vespers with Boston Baroque, Claudio in Handel's Agrippina at the festivals in Göttingen and Halle and for Harmonia Mundi records, the role of Satiro in Luigi Rossi's Orfeo at the Châtelet and for a European tour and Harmonia Mundi records, the role of Joas in Nicola Porpora's Il Gedeone with Martin Haselböck and Musica Angelica in Los Angeles, Frère Léon in Saint François d'Assise in the last composer- supervised production, performed at the Royal Festival Hall and live BBC television for the composer's 80th birthday, the role of Death in Victor Ullmann's Der Kaiser von Atlantis in productions at Helmuth Rilling's Bach Akademie in Stuttgart and with 2e2m at the Pompidou Centre and on tour, the title role in Pascal Dusapin's Roméo et Juliette at the Avignon Festival and for a European Tour, the title role in Toshio Hosokawa's Vision of Lear for the Munich Biennale and in Japan, the role of Il Testimone in the world premiere of Sylvano Bussotti's Tieste at the Rome Opera, the title role in Paul Mefano's Micromégas and the role of Lucifer in the world premieres of Karlheinz Stockhausen's operas Montag, Dienstag, and Freitag from Licht at La Scala and the Leipzig Opera and in Donnerstag aus Licht at Covent Garden.

He is an improviser who has performed with Steve Lacy, Joelle Léandre, Sainkho Namtchilak and David Moss. He has recorded for labels such as Erato, Harmonia Mundi and Naxos (8.559290). He has recently appeared in a Monteverdi program with La Venexiana in Lyon and is in the middle of a world tour with his own staging of Mauricio Kagel's Phonophonie.