Chief executive Ben Mansford has left Barnsley to join Championship rivals Leeds United.
Widely-respected Mansford joined Barnsley three years ago and leaves fresh from the Reds winning promotion to the Championship.
He has taken up the chief executive role at Elland Road and will work closely with Leeds chairman Massimo Cellino and executive director Paul Bell, with his primary focus being on football matters.
“I'm absolutely delighted to be joining Leeds United as their chief executive," Mansford said.
“Leeds is a city I know well and, throughout my career in football, I've experienced the atmosphere at Elland Road and the fantastic supporters the club has.
"The chance to work to take this club forward was one I had to take.
“I'd like to thank Patrick Cryne at Barnsley for the opportunity and support he has given me.
"What we achieved last year was nothing short of incredible and will forever live in the memory.
“I'm relishing getting started and meeting the staff, especially Garry Monk and his team.
"Everyone at Leeds United is truly committed to challenging to return to the Premier League and I can't wait to play my part in that journey."
Leeds chairman Cellino added: “I am very pleased to be welcoming Ben to Leeds United to join our expanding management team.
“It is important that we continue to grow our Football Club on and off the pitch, and I believe that Ben has the skills required to help us achieve our targets.
“He did a fantastic job at Barnsley and has an excellent reputation in the game.
“Ben’s arrival will now allow me to focus purely on my role as chairman and the running of the club.
"I look forward to working closely with him and Paul Bell at this exciting time for Leeds United.”
The Reds have announced Linton Brown will be acting chief executive and will join the board with immediate affect.