The Football Association hired Eccles last year to replace former comms chief Adrian Bevington when he moved to become Club England managing director after the 2010 World Cup in South Africa.
Eccles was previously director of comms at Ofcom from April 2007. Before that he was director of communications and corporate affairs at BSkyB.
He has also worked at British Interactive Broadcasting and as a special adviser to former culture secretary Chris Smith at the Department for Culture, Media and Sport.
FA general secretary Alex Horne commented: ‘I would like to thank Julian for his contribution to The FA and wish him well for the future. He has been very professional throughout his time here and I am grateful to him for introducing a number of valuable initiatives and ideas to the organisation.’
Eccles’ appointment received widespread coverage at the time due to a leaked FA briefing email, which asked ‘Haven’t you just appointed another Whitehall/Labour hack?’ along with a rebuttal.
Then chief executive Ian Watmore, who resigned shortly afterwards, emailed members of the FA board reportedly writing: ‘If I ever find the person who leaked the briefing then I will ensure that that person's reputation is damaged beyond repair.’