Chelsea have announced Ron Gourlay is to leave his role as chief executive.
Gourlay, who previously worked with Manchester United and sportswear manufacturer Umbro, departs on amicable terms to seek new opportunities.
A statement on the club's official website read: "Chelsea Football Club announces that Ron Gourlay, after 10 successful years at the club including five as chief executive, is leaving Chelsea in order to pursue new business opportunities."
Gourlay joined Chelsea in 2004 and worked as chief operating officer before succeeding Peter Kenyon as chief executive in 2009.
He departs with Chelsea top of the Premier League and determined to abide by UEFA's financial fair play regulations after presiding over a period in which the Blues won one Premier League title, two FA Cups, the Europa League and the 2012 Champions League.
He also helped to bring Jose Mourinho back to Stamford Bridge and negotiated a bumper sponsorship agreement with Adidas worth almost 300 million pounds over 10 years.
The club statement added: "The club, and in particular the owner [Roman Abramovich] and directors, wish to thank Ron for his many years of service to Chelsea and support his desire to seek new challenges.
"Ron's efforts have helped the club to achieve its position as one of the leading football clubs in the world. Pending additional appointments, chairman Bruce Buck and director Marina Granovskaia will assume additional executive responsibilities."
An exact timescale was not given for Gourlay's departure, with the prospect he could help smooth the transition to any new chief executive appointed.
"It has been a privilege to have played a role in the club's considerable achievements both on and off the pitch over the last 10 years, but I feel the time is right to move on to other challenges,'' Gourlay said.
"I would like to thank Mr Abramovich, the directors, the manager and players and all the staff for their support during my time at the club, and wish them much continued success in the future."