"This was a very difficult decision to make," says Stuart Dyble.
"My 12 years working with Ford, Aston Martin, Jaguar, Land Rover and Volvo have been the most rewarding of my career. I will forever remain passionate about these great brands and wish them all the best for the future."
A spokesman for Ford told AM: "His future employers will make an announcement with regards his new position in due course, but I can confirm he is leaving the automotive and PR industries."
Dyble worked in the role since August 2004, having moved there from his previous job as director of communications and public affairs for Jaguar, Land Rover and PAG.
Though Ford has not given any indication to who will replace him, an industry analyst told AM: "I can’t think of an obvious successor, but Tim Watson could be a possibility."
Tim Watson is vice president of communications and public affairs for Land Rover in North America. He has been in the role since January 2005.