John McCrea was born in Belfast, Northern Ireland, and also got his degree in Art and Design there. He presented his work to the editors of 2000 AD and Marvel UK, and got his first assignment doing a comic adaptation of 'The Centurions'. He then moved on to titles like 'Action Force' (British 'GI Joe') and 'BLAAAM!', as well as some 'Future Shocks' stories for 2000 AD.
In 1988, he began a cooperation with 18 year old writer Garth Ennis. Together they worked on 'Troubled Souls', 'For a Few Troubles More', 'Judge Dredd', 'The Demon' and 'Hitman'. They also came up with the band of superheroes 'Section 8'. McCrea has also worked with writers like Alan Grant, Doselle Young, Mark Milar, Warren Ellis and Ron Zimmerman.
Later on, he went to work for DC Comics and Marvel. He has drawn for such titles as 'Spider-Man: Get Kraven', 'Punisher', 'Batman: Legends of the Dark Knight', 'Hulk Smash', 'Wonder Woman', 'Teen Titans Go', 'Bart Simpson's Treehouse of Horror' and 'Star Wars Tales'