Donwood and Yorke met at the University of Exeter, as art students. After graduating, Donwood worked as a freelance artist in Plymouth, England, until asked by Yorke to produce the cover art for The Bends, beginning a long collaborative working relationship between the pair for Radiohead art and promotions. Yorke is usually credited alongside Donwood under the moniker "The White Chocolate Farm," or more recently "Dr. Tchock", "Tchocky" or similar abbreviations.

For his Kid A related work, Donwood produced a series of fiery, mountainous landscapes and a series of images centered around a minotaur. Donwood cites Caspar David Friedrich and Hieronymus Bosch, as well as time spent in war museums and mountain landscapes, as influences in its bleak, post-apocalyptic style.

In 2002, he and Yorke/Tchocky won a Grammy Award for Best Recording Package for the Special Edition of Amnesiac. Aside from his work for Radiohead, Donwood also maintains his own website, Slowly Downward, where he publishes his own short stories and various other writings, all of which have a unique and often odd style. Donwood's writings have also been used in his Radiohead album artwork, and frequently on Radiohead's official website.

Nine acrylic on canvas paintings, clearly inspired by Paula Scher's map paintings, provided the basis for 2003's Hail to the Thief's look, creating maps of war torn cities like Kabul and Grozny out of brightly colored blocks with politically charged words or phrases.

In 2006, Donwood began creating and selling large screenprints. In an interview with antiMusic.com, he explained it as an effort to reconnect with the process of print making and as a means to share his art in a larger format than the small, low quality prints in album cover and insert art, "It's a way of getting pictures out in the way they should be seen; not as 4-colour litho on cheap paper, but as real pieces of artwork that have a much greater visual impact."

Donwood's most recent exhibition, "London Views", is a series of fourteen woodcut-style prints of various London landmarks being destroyed by fire and flood. The prints are being exhibited in Lazarides Gallery, in Soho, London. The prints are also used as the cover and insert art for Thom Yorke's solo album, The Eraser.

In late 2006, Donwood exhibited the original paintings and other artwork done by him and Yorke for Radiohead albums, at a gallery in Barcelona. The exhibit focused on Kid A and later work, and a companion art book called Dead Children Playing was produced, credited to Donwood and Tchock.