Lucy appeared in shows, Grange Hill and Dream Team before getting the role that brought him to public attention, Luke Morgan in Hollyoaks. Lucy undertook a male rape storyline, for which he won the Best Newcomer Award at the 2000 British Soap Awards. Lucy then went on to do three series of the ITV drama Footballers' Wives where he played Kyle Pascoe, a football player for fictional club Earl's Park. In 2004 Lucy starred as Michael Sands alongside Ray Winstone in the ITV drama She's Gone. From 2005-10, he portrayed DS Will Fletcher in ITV's The Bill, and appeared in Sky1's The Match. In 2009 he took part in the one-off ITV drama, Whatever It Takes. The same year he resigned from The Bill to "explore other projects". He took part as a contestant in the fifth series of ITV's Dancing on Ice, paired with series regular Maria Fillipov. On 28 March 2010, Lucy made the finale finishing as runner-up. He appeared as Ben Lloyd on BBC One's Missing, which aired on 29 November 2010.
Lucy made his first screen appearance on 27 September 2012, as Danny Pennant in the BBCsoap operaEastEnders. On the 6th March 2013 it was announced that Gary would be returning to EastEnders as a permanent cast member.
In September 2014, Lucy will begin playing the role of Gaz in the touring production of The Full Monty.
Lucy attended Trinity Catholic High School in Woodford Green. In September 2006 he crashed his Honda CBR600RR outside Elstree Studios and badly bruised himself, delaying the filming schedule on The Bill. He has his own company, Gary Lucy Real Estate. also more recently Driving Lessons Finder, an internet based directory of driving schools and driving instructors. He manages several online E-shops for his parents and several smaller online niche stores. He has two children, India Jasmine Lucy (born 2005) and Elvis Lucy (born 2011) with partner Natasha Gray.