Kennedy appeared in many television dramas in the UK since 1983. He has appeared in Ashes to Ashes, Trial & Retribution, Ultimate Force, The Bill, Rose and Maloney, Waking the Dead, Reign of Fire and Holby City. He also played the role of Billy 'Two Hats' in William and Mary for three series.
He has played two roles in EastEnders; Dave Roberts in 2002, and Ray in 2006. He appeared in the 2007 film Wednesday and in the 2006 horror Attack Force with Steven Seagal. Kennedy portrayed Kepheus' general in the 2010 film remake of Clash of the Titans.
He currently portrays Dirk Savage in Hollyoaks, a role he has played since 2011. He is also the voice actor for Michael 'Psycho' Sykes in the upcoming video game Crysis 3.