Sumner is widely credited in advancing UK dance music, and the popularisation and technological advancement of sequencers. In the early 1990s, he collaborated with former Smiths guitarist Johnny Marr as Electronic.
Sumner was a founding member of Joy Division, a Salford band formed in 1976. The band is widely considered one of the most influential bands of the era. Primarily known as the band's lead guitarist (his main guitars were a Gibson SG and a Shergold Custom Masquerader), Sumner also played keyboards for synthesizer parts and made his first vocal appearance on record singing the chorus of "They Walked In Line" on the Warsaw album. In May 1980, the band's singer, Ian Curtis, committed suicide, resulting in Joy Division's end.
Sumner and remaining band members Peter Hook and Stephen Morris started a new band named New Order, joined by keyboardist Gillian Gilbert in October 1980. Though Hook, Morris and Gilbert also contributed vocals on some early tracks, Sumner emerged as the band's permanent singer and lyricist, alongside playing guitar and keyboards. Through a series of splits and reformations, the band have released ten studio albums.
In 1989, Sumner joined up with former Smiths guitarist Johnny Marr to form Electronic. The Pet Shop Boys' Neil Tennant collaborated on two tracks on their debut eponymous album, providing vocals. Sumner was their singer, guitarist, keyboardist and lyricist.
Bad Lieutenant included fellow New Order member Phil Cunningham and Jake Evans of Rambo & Leroy. Stephen Morris of New Order and Blur bassist Alex James also performed on the band's debut album. Sumner provided vocals, guitar and lyrics.