Alt-J (sometimes stylised ∆) was formed when Gwil Sainsbury (guitar, bass), Joe Newman (guitar, vocals), Gus Unger-Hamilton (keyboards), and Thom Sonny Green (drums) met at Leeds, UK University in 2007. The band currently resides in Cambridge.
Unger-Hamilton studied English Literature; the other three Fine Art. In their second year of studies, Newman showed Sainsbury a handful of his own songs inspired by his guitar-playing dad and hallucinogens, and the pair began recording in their dorm rooms with Sainsbury acting as producer on Garageband.
First as Daljit Dhaliwal and then as Films, they spent the next two years playing around town. Their eponymous first 4-track demo ∆, was recorded with producer Charlie Andrew in London and included early versions of "Breezeblocks", "Hand-Made", "Matilda" and "Tessellate".
Their first 2012 release for Infectious was the triangle shaped 7" "Matilda" / "Fitzpleasure", followed by "Breezeblocks" as an advance of their first album An Awesome Wave, released on 25 May 2012. That same year, they won the prestigious Barclaycard Mercury Prize for An Awesome Wave.
On January 2014, Sainsbury announced that he had left the band. "Hunger of the Pine" was released in June, with an accompanying video. Their second record, This is All Yours was released in September 2014.
On 6 March 2017 alt-J released "3WW", which features lead singer Ellie Rowsell of Wolf Alice, as a digital single and announced dates for the Relaxer Tour in support of the album. Three weeks later, on 29 March, they released "In Cold Blood", the second single from Relaxer.On 24 May 2017 alt-J released "Adeline", the third single from Relaxer. The album was released shortly afterwards, on 2 June 2017.
On September 28, 2018 an alternative version of Relaxer was released. The album, titled REDUXER, is a "rap heavy do-over" of the previous year's record.