Some of his works in film include the original scores for Denis Villeneuve's Prisoners, Sicario, and Arrival, and James Marsh's The Theory of Everything.

His only directorial work, Last and First Men, premiered at the Manchester International Festival in 2017, where he also performed the score live with the BBC Philharmonic Orchestra.

[1] Jóhann started his musical career in the late 1980s in the proto-shoegaze-influenced band Daisy Hill Puppy Farm, who released a couple of EPs which were played by British DJ John Peel and received a fan letter from Steve Albini.

The album combined holy minimalism, Satie, Purcell and Moondog with the electronic music of labels such as Mille Plateaux and Mego.

Pitchfork gave Englabörn a score of 8.9, and described it as "exceptionally restrained, the piano moving like droplets off of slowly melting icicles, the violin breathing warmth from above.

It was inspired by his father, an IBM engineer and one of Iceland's first computer programmers, who used early hardware to compose melodies during his downtime at work.

[7] Fordlandia, Jóhann's sixth full-length studio album, was released in November 2008 via 4AD, and was thematically influenced by the failure of Henry Ford's Brazilian rubber plant Fordlândia.

[8] In 2010, Jóhann collaborated with filmmaker Bill Morrison on The Miners' Hymns (2011), a film and accompanying composition for a brass band, pipe organ and electronics, based on coal-mining in County Durham.

The film was noted for celebrating "social, cultural, and political aspects of the extinct industry, and the strong regional tradition of colliery brass bands".

[13] Jóhann had scored a number of works concurrent with his solo career through the 2000s including the Icelandic comedy Dis in 2004, TV series Svartir englar in 2007, and In the Arms of My Enemy in 2007.

"[citation needed] Prior to his death he had been hired to compose the score for Disney's Christopher Robin, but died before he had begun work on it.

[18] His list of collaborators included Tim Hecker, Hildur Guðnadóttir, Pan Sonic, CAN drummer Jaki Liebezeit, Marc Almond, Barry Adamson, and Stephen O'Malley of Sunn O))).