James Clarke was born in London in October 1957. He has written over one hundred compositions, for symphony orchestra, solo musicians and for ensembles. They include nine works written for the Arditti String Quartet; four for the ensemble Klangforum Wien; several for the pianist Nicolas Hodges, including two for piano and orchestra; some for unusual forces, such as 2012-L for 200 musicians, 2014-Q for European and Asian instruments, and 2015-M for 308 musicians; a radio opera in collaboration with Harold Pinter. He has worked with some of the finest interpreters of new music, including, as well as those mentioned, Ernest Bour, Johannes Kalitzke, Harry Sparnaay, Ilan Volkov, Jürg Wyttenbach, Hans Zender, and the ensembles Apartment House, Linea, Phoenix and SurPlus.

Prestigious commissions have come from the BBC, French Ministry of Culture, Southwest German Radio, West German Radio, Beethovenfest (Bonn), the City of Darmstadt, Gaudeamus Foundation, Musik i Skåne (Sweden), the University of Cambridge, The Wigmore Hall (London), Wien Modern, the town of Witten, the Arts Councils of Great Britain, Greater London, and Northern Ireland, as well as from festivals in Amsterdam, Basel, Berlin, Bludenz, Dresden, Huddersfield, Leuven, Luxembourg and Riga. Important premieres have taken place at the Venice Biennale, in Donaueschingen, at the Lincoln Center (New York), at the Southbank and Barbican centres (London), and in many other major venues.

James Clarke has led composition courses at the Time of Music Festival in Viitasaari, Finland, where he was featured composer in 2000, and at the Festival junger Künstler Bayreuth in 2000-2003. In 2004 he was a featured composer at the Ars Musica festival in Brussels, where ten works were performed. He was composer-in-residence at Queen's University, Belfast, from 1994-97, and has lectured in Austria, Germany, Italy, The Netherlands, Russia, Sweden, UK, USA and in Azerbaijan, where he was appointed honorary professor at the Baku Music Academy. CDs of Clarke's music have been released on the labels Col legno, Corviello-Deutchlandradio, Composers' Art Label, Métier, NMC and others.