Stewart McIlwham began his studies at the Douglas Academy Music School in Glasgow with John Wiggins. He continued his studies at the Guildhall School of Music & Drama under Peter Lloyd, before being appointed Principal Piccolo of the BBC Philharmonic Orchestra in 1985, a position he held until 1990.
As a student Stewart McIlwham was a founder member of the National Youth Orchestra of Scotland, as well as playing with the National Youth Orchestra of Great Britain and the European Community Youth Orchestra. He was also a finalist in the Shell LSO Competition on two occasions in 1981 and 1985.
Stewart McIlwham was Principal Piccolo of the Royal Philharmonic Orchestra from 1990–97 before joining the London Philharmonic Orchestra as Principal Piccolo towards the end of 1997.
Stewart gave the world premiere of Sir Peter Maxwell Davies’s Piccolo Concerto with the RPO conducted by the composer at the Royal Concert Hall in Nottingham, followed by the London premiere at the Barbican in April 1997. In January 2019 he gave the UK premiere of Erkki-Sven Tüür’s Solastalgia for Piccolo and Orchestra at the Royal Festival Hall with the LPO conducted by Marin Alsop.
Stewart is currently Professor of Piccolo at the Royal College of Music in London. He joined the Board of the London Philharmonic Orchestra in 2003, and was President from 2012–19.