Astbury's family moved to Hamilton, Ontario, Canada, from the UK in 1973 when he was 11. He attended Glendale Secondary School. Astbury's early musical influences took root in Hamilton where he became an early fan of David Bowie, Iggy Pop and the New York Dolls. But he did not start performing until after his return to the UK.
In 1979, while living in Glasgow, Astbury was influenced by The Doors' song "The End", which he heard while watching the movie Apocalypse Now, later describing this as "a religious experience". In 1980, he was in Liverpool, where he was active on the punk scene based around Eric's Club. He moved to Bradford in late 1980, where he was a founding member of the positive punk band Southern Death Cult in 1981. Southern Death Cult lasted until March 1983. Along with guitarist Billy Duffy, bassist Jamie Stewart and drummer Raymond Taylor Smith, Astbury formed a new band, Death Cult and released The Death Cult EP. To gain broader appeal, the band changed its name to "The Cult" in January 1984 before appearing on the Channel 4 television show, The Tube.
The Cult have been a postmodern rock band active since 1983. Their first album, Dreamtime was released in 1984, and followed by Love in 1985. Love featured the single "She Sells Sanctuary", which introduced the band to an international audience. Many songs of these early albums focus on Native American themes, a pre-occupation of Astbury. On their third album, Electric, The Cult made a transformation to hard rock sound with the help of Rick Rubin.
In 1994, The Cult returned with an untitled album and a change of musical pace. Their hard rock sound was gone, replaced instead by Astbury's growing interest in alternative music, fashion and introspective lyrics. The self-titled album was not a commercial success, but released two singles ("Coming Down" and "Star"). To support the album they set out on a tour; in Brazil, however, Astbury's creative differences with guitarist Duffy reached their peak, and the former walked out on The Cult.
Astbury soon after assembled another group of musicians and began writing new songs. He called the group The Holy Barbarians, and in 1996 the band released the album Cream. Although this was not a commercial success. The band appeared at the small Tunbridge Wells Forum which saw them being joined onstage by Vic Reeves for a rendition of "Wildflower".
Personal difficulties and a drive for further introspection drove Astbury away from his new group, as he began working on a solo album (eventually released as Spirit\Light\Speed).
In 1999, Astbury and Duffy reformed The Cult. A new contract with Atlantic Records was signed, and in 2001 Beyond Good and Evil was released. The band enjoyed radio success initially with the single "Rise", until the band had a falling out with Atlantic and they ended all commercial promotions and radio play for the album. Astbury described the fight with the record label as "soul destroying"; disillusioned, he brought The Cult to another hiatus in 2002.
Astbury became lead singer of The Doors of the 21st Century in 2002. The group featured original Doors members Robby Krieger and Ray Manzarek. In 2003, Astbury also performed with surviving members of MC5 at the 100 Club in London, before finally reforming The Cult with Duffy again in 2006, for a series of live dates. In October 2007, The Cult released Born into This. The first single was "Dirty Little Rockstar".In 2009, The Cult announced a series of shows across Canada, the US, and various countries in Europe. It was billed as "'Love' Live", where the band performed its classic album, "Love," in its entirety.
On 29 May 2010 Boris performed "The End" with Ian Astbury at Vivid Festival on Sydney. Boris and Astbury released a four-song EP in September 2010 on Southern Lord and Daymare Records, containing four tracks entitled Teeth and Claws, We are Witches, Rain (The Cult cover), Magickal Child.
Astbury is featured on the UNKLE tracks "Burn My Shadow", "When Things Explode" and "Forever." He also sings "Flame On" on Tony Iommi's (Black Sabbath lead guitarist) solo album Iommi, as well as duets with Deborah Harry on her 1989 album Def, Dumb and Blonde's song "Lovelight". In 2010, he provided the vocals for the song "Ghost" on guitarist Slash's self-titled solo album. The track also featured former Guns N' Roses guitarist Izzy Stradlin on rhythm guitar. Astbury is also credited for playing the drums on a track called "Gasp" by "Japanese Cartoon."