Caan is currently appearing as a Dragon on the latest series of the BBC Two show.
Firefly has been tasked with targeting print, broadcast and online media in a bid to raise Caan's profile as part of its brief.
The agency has also been charged with handling PR for Caan's private equity firm Hamilton Bradshaw.
Firefly managing director Mark Mellor said: ‘The current Dragons' Den series on BBC Two has undoubtedly boosted James Caan's profile through the roof. The Firefly team will be involved in numerous high profile stories, as well as handling the increasing volume of news concerning interesting and diverse investments made by James and his private equity firm Hamilton Bradshaw.'
Firefly will work on news stories surrounding Hamilton Bradshaw investments, as well as James Caan's own personal activities and investments. Firefly's brief will also include speaker platform and brand endorsement opportunities.