Panos Pavlakis has left his role as Birmingham director, the Sky Bet Championship club have announced.
Pavlakis has been on the Blues board since January 2014 and helped run the club's affairs until Chinese firm Trillion Trophy Asia Limited completed their takeover in October.
A statement on the club's website read: "Pavlakis, who spent three-and-a-half years at Blues, has left to pursue other opportunities.
"The club would like to thank Panos for his service and efforts and wishes him the very best for the future."
Pavlakis' time at the club included the Blues twice escaping relegation on the last day of the season, the sacking of Lee Clark, Gary Rowett and Gianfranco Zola and the hiring of Harry Redknapp.
He wrote on Twitter: "That's it guys! 3.5 years with proper "Joys & Sorrows" on a proper Club! Thank you ALL for your patience! Good luck & God bless! £BCFC £KRO".