Sadie Harrison was born in Adelaide, Australia and moved to England in 1970. She gained her Masters and Doctorate in Composition at Kings College, London studying under Nicola LeFanu and David Lumsdaine. Performances of Sadie's works have been given by Lontano, London Chamber Symphony, Music Projects/ London, Ixion, Gemini, also the Kreutzer Quartet, Endymion, Capricorn, New Music Players, Sarah Leonard, Stephen Gutman, Composers Ensemble, Kokoro and the St. Christopherus Chamber Orchestra, Vilnius.

Recent projects include The Bride's Journey in Three Songs and a Memory for the Kaskados Trio, premiered in 2005 in Vilnius and broadcast live on European Radio; Bell Music for St. Casimir for the ABRSM Spectrum Clarinet Series 2005 and Scathach (Lady of Shadows) for the Scottish Clarinet Quartet commissioned for the Edinburgh Fringe Festival 2005. She is currently working on an opera based on the life of St. Christina the Astonishing with librettists Lesley Saunders and Jane Draycott. Her song cycle  what do winter's summers sing? won the International Greig Memorial Composition Competition 2005.

Her music has been broadcast on BBC Radio 3 and in Eastern Europe, Canada, Japan, Australia, America, Lithuania, The Netherlands and elsewhere and has been selected for several international festival performances. She was the only composer chosen to represent Australia at the ISCM World Music Days 2002 and her clarinet concerto 'The Fourteenth Terrace' was selected by the ISCM Australian Reading Panel this year to go forward to the World Music Days Zagreb 2005.