Stewart's musical career began playing guitar in Harrow-based band Ritual. Ritual gigged extensively in London's gothic rock/ post-punk scene but rarely outside. Ritual's first output was a 4 song radio session for BBC Radio 1 DJ John Peel in 1981. This led the way for a self-compiled and released cassette album, Songs for a Dead King, which was available only at gigs and by mail order. In 1982, Ritual signed to Red Flame Records and released one single, "Mind Disease" and one EP, Kangaroo Court.
The Cult
In 1983, Ritual drummer Ray Mondo was recruited by Ian Astbury and Billy Duffy to form a new act entitled Death Cult. Stewart, after prompting from Mondo, attended auditions for the Death Cult bass player role and was subsequently hired. From their beginning, Death Cult had a commitment to Beggars Banquet Records. In April 1983, Death Cult released an EP, Death Cult, on Beggars offshoot label Situation Two. In Sep 1983, Ray Mondo was replaced by Nigel Preston, Duffy’s former bandmate in Theatre of Hate. At the time, Preston was playing with post-punk/ goth band Sex Gang Children. A drummer swap was agreed between the bands, feeling that the playing styles of each drummer were better suited to the future direction of the other band. In October 1983, Death Cult released a single, "God's Zoo", with Preston on drums. The group changed their name to The Cult minutes before a live performance of the song Spiritwalker on UK TV's Channel 4 series The Tube. Stewart continued to play bass on all Cult recordings until 1990. He also played keyboards on several songs on the Love. Following the recording of the band's third long-player, Electric, in 1987, the band felt that a second guitarist was needed on tour to reproduce the music of Electric. The role was filled by Stewart, having a familiarity with the songs and style, and being a former guitarist. For the tours, Kid Chaos was recruited as bassist. Stewart continued to appear on bass in the first two promotional videos for Electric - Love Removal Machine and Lil Devil. The 5 piece line-up with Stewart on guitar was used for the 3rd video, Wild Flower. Stewart moved back to bass for the recording and touring of the Sonic Temple album. Keyboards for the recording were played by John Webster, and by John Sinclair on tour. In 1990, following the tour, Stewart left the band, citing the distance that had grown between Astbury and Duffy, and a wish to start a family, as the main reasons for departure. His final appearance with The Cult was at the Universal Amphitheater in Los Angeles on 3 April 1990.
Having relocated to London, Stewart moved into studio work, producing an EP on Beggars Banquet Records for Goat, featuring Adrian Oxaal, later guitarist with James. During this time, Stewart joined Adrian Smith in a low-key band The Untouchables, playing informal gigs, mainly around London. In 1991, following the birth of his daughter, he moved with his family to Toronto, Canada, to pursue a production career. In 1992, Stewart produced the Joni Mitchell song A Case of You with Toronto-based band Sloan for the tribute album Back to the Garden. The song became the album’s most successful single. In 1993, Stewart worked at Le Studio, in Morin Heights, Quebec, with the band Les Respectables. The recordings remained unreleased until some songs surfaced on their 1996 album Full Regalia. Stewart worked with Ripped in 1994 to produce songs for their debut album Bloodshot. While in Toronto, Stewart also took other opportunities for studio performance. In 1993, he co-wrote, produced and played bass on an EP for Polygram Canada with Toronto singer/ guitarist Ed McDonald, entitled Masterstroke. In 1994, he played fretless bass on Memory Thief, the second album by Polygram artists Lost & Profound.
On 10 October 2009, on a tour celebrating the 25th anniversary of the release of the Love album, Stewart played bass again with his former bandmates on stage at London’s Royal Albert Hall for two encores, The Phoenix and She Sells Sanctuary. He was also joined onstage by the original drummer for the recordings, Mark Brzezicki. Again, for the 25th anniversary of the release of the Electric album in 2013, Stewart made several other guest appearances:
26 October 2013 - Glasgow Barrowland - Love Removal Machine, Horse Nation & Spiritwalker
31 October 2013 - London Roundhouse - Love Removal Machine, Horse Nation & Spiritwalker
1 November 2013 - London Roundhouse - Sun King & Horse Nation.