In a statement issued by the club, it was announced he's stepping down to take up a position with The Topps Company, but will remain as a director of the club.
The announcement of a new CEO will be made shortly and Mark will remain until the end of the month to aid the transition.
He arrived at Fratton Park in October 2012 to work voluntarily with the Pompey Supporters’ Trust and Presidents in helping save the club from extinction.
Mark was then appointed CEO as liquidation was avoided and, over the next few years, existing debts of more than £8 million and annual losses of more than £1 million were erased during the recovery from administration. The club successfully completed a move to a new training facility in the city in 2015, while Mark remained as chief executive during the transition from fan to Tornante ownership during the summer of 2017.
Pompey chairman Michael Eisner said: “Mark is one of the best businessmen I have known throughout my career and he has led Portsmouth Football Club with courage and tenacity from the dark days of administration to the bright and hopeful place we are today.
“I will continue to value his professional contributions – both as a member of the Pompey board and in his new role at Topps – and his friendship.”
Mark said: “It has been an absolute honour and privilege to have been CEO of Portsmouth Football Club. To represent this club and our supporters – I would argue some of the most loyal and passionate in the world – has genuinely been the greatest experience of my life.
“I have been extremely fortunate to work as part of a larger team throughout this period, with people who care passionately about Pompey. Whether staff, director or fan, we all share a deep love and emotional attachment to the club and city.
“Football isn’t an exact science and the ups and downs are all part of the emotional rollercoaster of caring so much about the club. If you don’t hurt with the lows, you can’t experience the joy and emotional feelings of the highs – the two are entwined. Taking on this exciting new challenge as General Manager of International Sports and Entertainment at The Topps Company enables me to continue my association with Portsmouth Football Club as it embarks on an exciting new era – both on and off the pitch.
🗣 "I felt the time was right to look for a new challenge"
— Portsmouth FC (@Pompey) May 14, 2021
👔 Departing CEO Mark Catlin discusses his decision to step down and looks back on his time at #Pompey
“I want to thank Pompey fans for their support of the club during my time as CEO. It’s impossible to always agree in such a subjective sport and I have always welcomed opinions, whether they are positive or negative, from you all.
“In Michael Eisner and the board we have incredible owners. In Danny and Nicky we have an amazing new management team, and in Greg Miller we have an outstanding, bright academy manager. Along with the rest of the off-field team, who so much credit goes to, we are lucky to have an array of individuals who are some of the best – if not the best – in their relative areas of expertise, across all divisions.
“We are perfectly positioned to continue to build on the progress made, on and off the pitch, during my time as CEO.”
