Sharp made his debut in the 1980s for the famous science-fiction magazine 2000 AD after a year's apprenticeship with the legendary Don Lawrence, artist on the seminal Dutch comic Storm. His works included many Judge Dredd stories. Sharp's fame increased markedly when he moved to Marvel UK, for which he drew the famous mini-series Deaths Head ll Thereafter he began working mainly in the US on books as diverse as X-Men, Hulk, Spider-Man, Venum, Man Thing (for Marvel Comics), Superman & Batman for DC and Spawn for Image (McFarlane).

Sharp has also worked on more mature themed books for Verotik, doing GOTH, Jaguar God and Frazetta's "The Death Dealer".  Later he co-created the  Wildstorm series The Possessed with writer  Geoff Johns and a strip for Heavy Metal magazine, entitled "A-crazy-A" featuring Playboy model Tiffany Taylor- for which he provided the art and script. Likewise for a short story in vampirella magazine called "Winter Rose".

In 2004 Sharp set up his own publishing company,  Mam Tor Pub., with wife Christina McCormack to publish the artbook Sharpenings: the Art of Liam Sharp.

After the early success with this, Sharp saw a hole in the comic book market for alternative independent comics, and together with his wife Christina, designer Tom Muller and friend John Bamber set out to expand the company to start publishing more work. This saw the launch of the critically acclaimed and award –winning anthology, Mam Tor: Event Horizon.

Sharp went on to illustrate the controversial and critically well-received  DC Vertigo comic Testiment , and the  Countdown-related title,  Lord Havok and The Extremists. He is now providing the art for the Wildstorm title based on the video game Gears of War.

Mam Tor and the advertising agency Mother produced a free sixteen page comic given away from with Time out for which Sharp was the art director, as well s providing the art for a story in the first two issues as well as the cover for the first issue.

In September 2008 he signed an exclusive deal with DC.

Sharp has also written the novel God Killers.