The division will offer strategic advice, rights negotiation, rights activation and measurement.
Stephen Allan, chairman and chief executive of MediaCom, said: "MediaCom has previously focused its sports expertise at a local and regional level, but we realised our clients now require a more global and deeper understanding of the sports arena as their budgets continue to shift towards investments in this area and, with it, a much greater sensitivity to achieve solid returns."
John's remit will be to work with the WPP agency's global account directors to manage the relationship with key sporting bodies and to provide clients with access to opportunities.
He will also work closely with the MediaCom Beyond Advertising team and GroupM's Entertainment and Sports partnership group.
John spent 10 years at IMG, most recently as senior vice-president and managing director of IMG Consulting Asia-Pacific.
He has advised clients including Visa, GE and Hyundai, and was responsible for the first Beijing Olympics deal to exceed the $100m mark.
MediaCom's global clients include Volkswagen, Dell, Shell and Procter & Gamble.