Damian Willoughby, Chelsea's commercial director, was sacked for sending "inappropriate messages" to a female football finance agent.
Inappropriate texts were exchanged by Willoughby to Catalina Kim before he joined the club last month.
"Chelsea confirms that it has terminated commercial director Damian Willoughby's employment with immediate effect," a club spokesperson said.
"Evidence of inappropriate messages sent by Mr Willoughby, prior to his appointment at Chelsea FC earlier this month, has recently been provided to and investigated by the club.
"While they were sent prior to his employment at the club, such behaviour runs absolutely counter to the workplace environment and corporate culture being established by the club's new ownership."
Following the club's acquisition by an investor group led by billionaire Todd Boehly and Clearlake Capital, Willoughby started a second stint there last month.
Between 2007 and 2010, Willoughby worked at Chelsea. He has also worked for Manchester City and EA Sports. But after only a month in the position, he was fired.