Guy trained at the Guildhall School of Music and Drama, studying saxophone but also learning clarinet, flute and oboe. He now performs with a wide range of large and small ensembles, from orchestras to folk and rock groups. He co-founded award-winning chamber quartet Kaleidoscope, with whom he has performed extensively across the UK including appearances at the Wigmore Hall, Bridgewater Hall and the Purcell Room, as well as winning accolades from organisations such as the Hattori Foundation, the Tunnell Trust, the Worshipful Company of Musicians, the City Music Foundation and the Park Lane Group.
As a multi-instrumentalist, Guy performs and records on saxophone, clarinet, flute and oboe with a wide range of groups and artists including Britten Sinfonia, Paul Weller, London Metropolitan Orchestra, Hannah Peel and Will Burns, and The Magnetic North. He is also regularly engaged as a theatre pit musician for shows in the West End, National Theatre and touring productions across the country.