Lisa Illean is a composer of acoustic and acousmatic music, based in the U.K. Her music has been described as "exquisitely quiet shadows shaded with microtunings" (The Sydney Morning Herald) and "a compelling exercise in stillness and quietude" (The Australian). Illean's work spans pieces written for orchestra to those commissioned for new, prepared or adapted instruments, and sound works conceived for unique spaces. This has led to her presenting music around the globe, including at Festival Présences (Paris), Donaueschinger Musiktage, Wittener Tage für neue Kammermusik, Time:Spans (New York), Taiwan International Festival of Arts, the BBC Proms, Unerhörte Musik (Berlin), Angelica Festival (Bologna), Huddersfield Contemporary Music Festival, Tzlil Meudcan (Tel Aviv), Transit Festival (Leuven) and November Music (S'Hertogenbosch), in venues ranging from Elbphilharmonie (Hamburg) to the industrial bays of Sydney's Carriageworks and London's Café Oto.

Many of Illean's compositions arise out of working with non-tempered tuning systems, playing close attention to sonority, subtly unfolding harmonic forms, auditory phenomena and perspective. In recent years she has oriented her practice as a composer to include making long-form pieces with both performed and pre-recorded material, in close development with one or two others. This process incorporates unadorned, 'everyday' instruments—often simply-made zithers; exploring visual analogies and tactile ways of sketching. She has also made a number of pieces for voice, including A though-grown earth (2018) for Juliet Fraser and Sleeplessness ... Sails (2018) for Sarah Connolly. Cantor, for soprano and ensemble, was named Instrumental Work of the Year at the 2018 Australian Art Music Awards.  

Premiered in 2017 by members of the Philharmonia, Januaries for ensemble has since been programmed by seven other ensembles in the U.K., U.S. and Australia. Land’s End, premiered by the Sydney Symphony Orchestra and David Robertson, has been taken up by the BBC Symphony Orchestra, Adelaide Symphony Orchestra and the orchestra of the Australian National Academy of Music.

She has been most recently commissioned/performed by Ensemble Intercontemporain (ever-weaver), Trio Accanto/Experimentalstudio des SWR (Tiding II), Juliet Fraser/Explore Ensemble, guitarists Yaron Deutsch, Sean Shibe, Sam Cave and Huw Davies (Tiding), Adelaide and Melbourne Symphony Orchestras, London Sinfonietta, Tritium Trio and Ukaria Cultural Centre (for musicians from the Australian National Academy of Music, electronics and pianist Aura Go). She is published by Faber Music. In autumn 2024 Cédric Tiberghien will premiere Sonata in ten parts, Illean's first work for solo piano, commissioned by Wigmore Hall.