Roach started in the comics industry with his self-published fanzine Hellfire in the 1980s. In the mid-1980s, he advanced to the point of becoming a penciller on 2000 AD, England's premiere comics anthology, on such strips and series as Conqueror, Galaxy Rangers, Synnamon, Judge Anderson, and the headlining Judge Dredd. He still contributes to the title occasionally to this day.
He was also one of the artists on Alan Moore and Neil Gaiman's critically acclaimed revival of the series Miracleman for Eclipse Comics.
Roach began penetrating the American comics market in the 1990s, with contributions to DC Comics--on such varied titles as Batman, Batman and Demon, Green Lantern, Green Arrow, Lobo, Dark Stars, Challengers of the Unknown and a comics adaptation of Babylon 5--and Dark Horse, where he contributed early art for the Star Wars: Tales of the Jedi series and, of course, Aliens.
More recent comics work for Roach has included a number of Star Trek adaptations for Wildstorm Comics in the early 2000s. Other comics companies he has worked forinclude Panini Comics, Marvel, and Topps.
Roach is also associate editor of the U.S. based magazine Comic Book Artist, which is dedicated to the historical representation of comic-book characters. Roach was co-editor of The Warren Companion: The Definitive Compendium to the Great Comics of Warren Publishing (2001) the revised edition of the Slings and Arrows Comics Guide (2003) and The Superhero Book: The Ultimate Encyclopedia of Comic Book Icons and Hollywood Heroes (2004).
Roach has worked as illustrator for consecutive Dungeons & Dragons role playing game book titles for publishers Wizards of the Coast.
Roach's recent work has included working as storyboard artist and penciller of accompanying graphic novel, Hard Choices 'What happened on Algol?' for Ultramarines: The Movie, both written by Dan Abnett and released on 29 November 2010.
Roach is based in Wales, United Kingdom.