Formed in 2007 in the English city of Leeds by Joe Newman (vocals, guitar), Gwil Sainsbury (guitar, bass), Gus Unger-Hamilton (keyboards, vocals) and Thom Green (drums), alt-J won the 2012 Mercury Prize , with their debut album, An Awesome Wave, released that year on the Infectious Records label.

alt-J, also known by the symbol Δ (delta) - which on the Macintosh is formed by typing the sequence "alt" + "J", lost a member in early 2014, when Gwil Sainsbury announced his departure from the group. As a trio, the band released their second album, This Is All Yours, in September of the same year. In 2017, the band released Relaxer. The trio returned in 2022 with The Dream.