Dillon studied art and design, linguistics, piano, acoustics, Indian rhythm, mathematics and computer music, but is self-taught in composition.
The recording of his chamber opera, Philomela, won the Grand Prix de l’Académie du Disque Lyrique 2010.
His major works include choral and vocal music, including the cycle L'évolution du vol (1993) and the opera Philomela (2004), the orchestral works helle Nacht (1987), ignis noster (1992), Via Sacra (2000), and La navette (2001), as well as a violin concerto for Thomas Zehetmair (2000) and the piano concerto Andromeda (2006) for his partner, Noriko Kawai, all showing an ease of writing for large forces.
[3] Andrew Clements of The Guardian awarded it a full five stars, describing the last movement ("Oceanos") as having a "Wagnerian grandeur" and stating, "The cumulative power of [Nine Rivers] is massive, the range of musical experience vast.
"[4] His considerable body of chamber music, often written expressly for a performer's individual abilities, includes solos for clarinet, drumkit, cello, flute, piccolo, guitar, violin, viola, and accordion, alongside nine string quartets (1983, 1991, 1998, 2004, 2008, 2010, 2013, 2017, 2018), the five-part Book of Elements for piano (1997–2002) and the soadie waste for piano and string quartet (2002/3).