Mark Catlin has announced that he will be stepping down from the position, though he will remain with the club as a director.
Arriving in 2012, he oversaw the transition as Pompey went from a club on the brink of destruction, to being saved by the fans and finally becoming a profitable venture once more.
Working alongside the Pompey Supporters’ Trust, Catlin spent most days with the chairman at the time, Ashley Brown.
Mr Brown said: ‘For four or five years we spoke to each other basically every day, and he’s been at the centre of everything Pompey since the supporters managed to save the club.
‘Even now, we still catch up from time-to-time. Mark is the sort of person you can have a frank conversation with, and I’ve always respected that about him.
‘We didn’t always see eye-to-eye on things – in fact we frequently disagreed on footballing issues – but at the end of the day you could always shake hands and have a glass of wine with him.
‘He’s a very easygoing CEO and definitely big shoes for the club to fill.’
During his time at the club, Catlin has immersed himself in many aspects of the club.
He has also become a trustee for Pompey in The Community (PITC), which is the club’s charitable arm that works on community outreach projects.
Charity CEO Clare Martin says Catlin has always been at the other end of the phone for her.
‘With him staying on as a director I’m sure he will still be involved in PITC in some capacity,’ she said.
‘It’s been great to have such an approachable chief executive, you can just pick up the phone and he will answer.
‘Mark has been with the club for a long time now – time really has flown by. But we’ve always been there for one another and he’s had a tremendous impact on this football club.
‘The work he has put in will never be forgotten.’