Garth Knox was born in Ireland and grew up in Scotland. Being the youngest of four children who all played string instruments, he was encouraged to take up the viola, and he quickly decided to make this his career. He studied at the Royal College of Music in London with Fredrick Riddle, where he won several prizes for viola and for chamber music. Thereafter he played with most of the leading groups in London in a mixture of all repertoires, from baroque to contemporary music.
In 1983 he was invited by Pierre Boulez to become a member of the Ensemble InterContemporain in Paris, where he had the chance to do much solo playing (including concertos directed by Pierre Boulez) and chamber music, touring widely and playing in international festivals.

In 1990 Garth Knox joined the Arditti String Quartet, playing in all the major concert halls of the world, working closely with and giving first performances of pieces by most of today's leading composers including Ligeti, Kurtag, Berio, Xenakis, Lachenmann, Cage, Feldman and Stockhausen (the famous "Helicopter Quartet").

In 1998, Garth Knox left the quartet to concentrate on his solo career. As a soloist, he has given premieres by Henze (the Viola Sonata is dedicated to him), Ligeti, Schnittke, Ferneyhough, James Dillon, George Benjamin and many others. Recent appearances have included concerto appearances in Cologne, solo recitals in Brussels, Vienna, Paris etc as well as broadcasts for the WDR in Germany including the first performance of a viola duo by Peter Eotvos with Tabea Zimmerman, and a series of duo concerts with Kim Kashkashian.

He has recently become a pioneer of the viola d'amore, exploring its possibilities in new music, with and without electronics, and is in the process of creating a new repertoire for this instrument.

Garth Knox now lives in Paris, where he enjoys a full time solo career, giving recitals, concertos and chamber music concerts all over Europe, the USA and Japan. His recently released solo CD (MO 782082) won the coveted Deutsche Schallplaten Preis in Germany, and his lates CD "Spectral Viola" (edition zeitklang) has been highly acclaimed. He now lives in Paris and is currently professor of viola at Musikene in San Sebastian.