James Dillon was born in Glasgow, Scotland, and his music has been published exclusively by Peters Edition since 1982. In that year, Parjanya-Vata, for solo cello, won the Kransichsteiner Musikpreis at the Darmstadt Ferienkurse für Neue Musik. The work's Sanskrit title refers to the ancient Vedic hymns in which "parjanya" and "vata" are the personifications of rain and wind. Dillon studied Indian music during the early 1970s with Punita Gupta, and some of the rhythmic techniques that he encountered are referred to in 1978 composition Ti.re-Ti.ke-Dha, for solo percussionist. Dillon was re-invited by Darmstadt to present new works throughout the 1980s and early 1990s.
In 1983, the First String Quartet received its premiere from the Arditti Quartet at the Huddersfield Contemporary Music Festival. The Arditti Quartet has remained closely involved with the composer, and Huddersfield is one of the many festivals to feature Dillon's music. It mounted a large-scale retrospective in 1995.
In the mid-1980s, Dillon began his German Triptych, a set of works based on the idea, the composer says, of "illumination as the emanation from darkness", a recurring theme in Western art. Überschreiten from 1985 was commissioned by the London Sinfonietta, this was followed in 1987 by Helle Nacht, Dillon's first work for large orchestra. Richard Toop described this massive piece as "a music full of figures which, like the stars, are intense, yet seem almost infinitely far away". In 1994 a collaboration between Grateful Dead’s Phil Lesh (Rex Foundation) and the BBC made possible a recording of Helle Nacht, together with Dillon's 1992 BBC Proms commission ignis noster, under conductor Arturo Tamayo and the BBC Symphony Orchestra. After an interval of some years, the German Triptych was completed with the 1996 flute concerto Blitzschlag. This work was given its premiere at the Edinburgh Festival by soloist Pierre-Yves Artaud and the BBC Scottish Symphony Orchestra under Martyn Brabbins.
Throughout the 1980s and 1990s, James Dillon worked on Nine Rivers, an ambitious group of large-scale pieces that the composer conceived, not as a cycle, but as a collection of works with certain "internal symmetries". The nine works are scored for various forces, ranging from the solo percussion and electronics of La coupure, through ensemble pieces such as East 11th St NY 10003, to the largest works - Viriditas, for sixteen solo voices, and Oceanos. This last piece, the "ocean of oceans", is Nine Rivers' delta, bringing together all the forces previously deployed throughout the series and including more than fifty musicians and live electronics. Oceanos was commissioned for the BBC Proms 1996, and the first performance was given by conductor Richard Bernas and Music Projects/London. As well as the BBC, commissioners for other pieces in the Nine Rivers series include IRCAM, Ensemble InterContemporain, the Oslo Sinfonietta and Glasgow 1990 European City of Culture.
Dillon says that he embarked upon the Nine Rivers project in part to escape both the frustratingly "atomistic" nature of a composer's activities and the normative structures of the concert format. The intricate references of this massive and complex meditation on time range from environmental concerns to the nature of musical language connected through the metaphor of the river. Other grouped works include: L'évolution du vol, a song cycle for female voice and chamber ensemble; the violin series that makes up Traumwerk, of which the first book, for two violins, won the1997 Royal Philharmonic Society award for chamber-scale composition; and The Book of Elements, a cycle in five volumes for solo piano inspired by the pianist Roger Woodward, Volume 5 of which won Dillon a rare second Royal Philharmonic Society Award in 2003.
James Dillon's Violin Concerto was his third BBC Proms commission, and was premiered to great acclaim in the 2000 season by soloist Thomas Zehetmair and the BBC Scottish Symphony Orchestra, conducted by Martyn Brabbins. Here, Dillon sets the piped drones and nimble fiddlework of the Scottish folk tradition against the overlapping webs of sound that have always characterized his virtuosic use of the orchestra. As in the earlier Blitzschlag both soloist and orchestra are engaged in a dance; like the moth and the flame, there is a strange attraction. Other recent orchestral works include the four-movement Via Sacra, commissioned by the Société Philharmonique de Bruxelles to celebrate the city’s Millennium project, and La navette, a single-movement work commissioned by SWR for performance at the Donaueschingen Musiktage 2001.
Dillon’s opera Philomela further explores the material of La navette. Premièred in Oporto in September 2004, Philomela sets Dillon’s own libretto, based on the myth of Philomela’s rape and torture by Tereus and her subsequent weaving of the story. Recorded on the French label Aeon with the original cast, Philomela was awarded the Grand Prix du Disque.
In January 2005, Dillon completed his Fourth String Quartet, which was premièred in March 2005 by Quatour Diotima. This work earned Dillon a unique third Royal Philharmonic Society Award for Chamber Scale Composition, and was praised by the RPS for its "imperishable musical values and active awareness of the tradition of string-quartet [...] a reminder that Dillon has made one of the most distinctive contributions to the music of our time". His piano concerto Andromeda was premiered by Noriko Kawai and the BBC Scottish Symphony Orchestra at the 2007 BBC Proms. In 2007 he completed a new work Physis for the Orchestre de Paris and more recently completed his 3 Triptychs for three different ensembles Ictus (Bruxelles), Cikada (Oslo) and Talea (New York.)
Dillon is closely associated with a number of the world’s leading contemporary music ensembles. He has been a guest lecturer at many universities throughout the world, and was named Distinguished International Visitor by New York University in 2001-2002. In 2003 he was awarded an honorary doctorate by the University of Huddersfield.
In 2007 Dillon accepted the position of Professor of Composition at the University of Minnesota, Minneapolis/Saint Paul. In 2011 Dillon became the most celebrated winner in the RPS Music Awards history when his Nine Rivers won the Large-Scale Composition Prize.