Foss started working as an artist in his teens, in Guernsey, creating signage for local companies. While studying at Magdalene College, Cambridge, he started pursuing professional magazine commissions, including the then recently launched Penthouse magazine. He went to a boarding school in Dorset; his master encouraged him to train for an art scholarship.
Books featuring Foss illustrations include the 1970s British paperback covers for Isaac Asimov's Foundation Trilogy, several of Edmund Cooper novels, and E. E. "Doc" Smith's Lensman and Skylark series. Some of the art he did produce was specific to the stories and some examples of this are the covers he did for the Grafton publications of the Demon Princes novels by Jack Vance in the late 1980s, Star King, The Killing Machine, The Palace of Love, The Face and The Book of Dreams. Not being a fan of science fiction, Foss typically did not read the books he illustrated, preferring to paint scenes entirely from his imagination. In 1975, Foss was hired by director Alejandro Jodorowsky for an intended film version of the science-fiction novel Dune by author Frank Herbert. He delivered several conceptual studies published in the book 21st Century Foss,, containing a foreword by Jodorowsky. The project failed. In 1977 Foss worked for several months on studies for the movie Alien and also did some designs of the planet Krypton for the movie Superman. Some of his crystal structures for the planet were realised in the movie, although they were used as ice-structures. During this period Chris Foss illustrated the sleeve of the album Clear Air Turbulence for the Ian Gillan Band. Painter Glenn Brown controversially appropriated individual space scene paintings by Foss and in the one case copying and altering it and in the other, leaving it entirely unchanged. The titles of these works reference the vocalist of the bandJoy Division, who died by his own hand. Chris Foss created much of the color concept art for Sweetpea Entertainment's Traveller franchise, as produced by Imperium Games. He produced 12 pages of artwork for the new Traveller edition's first supplement, Starships. He also illustrated a number of covers for Imperium's Traveller.
''Diary of a Spaceperson''
In 1990, Foss released a book that was vague in many of the details of its production called Diary of a Spaceperson, published by Paper Tiger. It is a tome of his work to date. However, there is no way of knowing what that date is, which in some way provides some potency to the story within, as it is stated in the foreword that "the contents of the book are extracts of a 'spaceperson's diary' and are duplicated within", and "that the dates published within are of no meaning". Although there is a vast number of his paintings within the book, hardly a large percentage of what he has produced is featured, and the fictional diary text itself also bears little connection to the paintings, except in some contrived ways. There is also no mention of the actual or original titles for any of the featured artworks, but many have been seen on the covers of authors' science fiction. It also features many sketches in various states of completion, some of which are seen completed and painted in other parts of the book. In fact only some of the images, all of which feature architecture and craft, are rendered in paint; the rest of the works are nudes and sketches of women.
''The Joy of Sex''
In contrast, Foss's numerous illustrations for the sex manualThe Joy of Sex are done in a much softer, natural style. The illustrations were based on photographs taken by Chris in his studio in Fulham, London.