Gaynor will be based in Hong Kong and report to worldwide chair and CEO Donald A Baer. She has spent the past 12 years as managing director and founding partner of Reputation, an Australian consultancy.
Ford will continue to serve in his separate roles as worldwide vice chair and chief client officer, and as regional chair during the transition period.
Her areas of specialisation include corporate communications, government relations and investor relations. Former clients include Nike, IBM, Bupa, Manulife, Jardine Matheson, Deutsche Bank, Marriott International, Qantas, KPMG and Optus.
In a statement, Baer described Gaynor as "an extraordinary communications professional who brings strong entrepreneurial drive".
Gaynor began her career in the Commonwealth Government, where she spent a decade working on policy development, communications and training for government agencies across Australia.