Ewins studied Conceptual Art at Goldsmiths College, where he was also taught fine art by Michael Craig-Martin.[2] Ewins met future collaborator Peter Milligan at Goldsmiths, and left in 1977. In 1980, Ewins held a solo exhibition of his work at Frestonia's Car Breaker Gallery in London,[3] a squat in Ladbroke Grove's Republic of Frestonia.[4] Ewins formed a long-term collaborative partnership with fellow artist Brendan McCarthy who also showed at the Car Breaker Gallery, creating the comic Sometime Stories, which faltered after the first issue leaving the second issue completed but unpublished. On the strength of Sometime Stories, Ewins soon started providing covers for 2000 AD, the first being issue #33 published in October of the same year.
Ewins and McCarthy continued working together on Future Shocks and Judge Dredd, but soon after Ewins began working solo on Rogue Trooper and later Judge Anderson. In 1985 Ewins started working on Bad Company, a sci-war epic, written by Peter Milligan with artwork by Ewins and Jim McCarthy (brother of Brendan).
Along with Steve Dillon, he started the comic magazine Deadline in 1988, which continued for another seven years.[2] At the same time as Ewins was starting Deadline, he began working on Skreemer for American comics publisher, DC. Ewins was also still contributing art to 2000 AD at the same time. This level of work was to have a serious impact of Ewins' health.
He "suffered a serious breakdown from overwork" in 1991 and was unable to take on work that had a deadline, which led to lost commissions from DC Comics and Penguin Books.[6] His plan to recover was to create an anthology based on work from friends in the industry like Peter Milligan, Alan Grant and Alan McKenzie, as well as friends like musician Michael White. The volume was finished off with "Machine", a story written by Ewins based on his breakdown.[7] He worked on the stories from 1995 to 2003[6] and the book was published as The Dark Gate in 2004 by Cyberosia Publishing.
Ewins also was a painter and had a number of exhibitions. Ewins was also an influence on street art, especially The IFC and the Mutoid Waste Company, and a Ewins-influenced exhibition was held in November 2011.[8]
In January 2012 it was reported that he had sustained head injuries during a confrontation with police, in which one policeman received stab wounds.[9] He subsequently appeared before Uxbridge Magistrates Court in February 2012 charged with causing Grievous bodily harm with intent.[10]