Crowther will be returning to the US at the end of the year for personal reasons, confirmed Stephen Allan, worldwide CEO of MediaCom.
Heap's hire is described by GroupM as a "return of sorts", as he left Mindshare China for PHD in 2008 and has been CEO of PHD China since 2010. During his tenure, Heap has grown PHD's China office from 10 to 280 employees and was instrumental in winning the Unilever media account in China. He was also named Greater China Agency Head of the Year by Campaign Asia-Pacific last year, an honour given to the best CEO across all media, advertising, digital and PR agencies in China, Hong Kong and Taiwan.
This is a significant step up for Heap, as he will be moving from running a single, albeit major, market to an entire region that includes 21 offices in 15 countries and a staff of more than 1,400.
It is understood that after joining MediaCom, Heap will have a 'cooling off period' of about six months before working on P&G, to prevent client conflict.
Crowther has elected to move back to his home in Detroit and is understood to be in conversations with Aegis Media on a global role handling the US$3 billion-dollar General Motors account.
Since joining MediaCom in 2010, Crowther has won the network business from major companies including Dell, Coca-Cola, Fonterra and P&G.
Crowther will stay with MediaCom through December to oversee the transition.
"Alex and I both feel that Mark is the perfect person to lead MediaCom on the successful course that Alex has set for us," Allan said. "Mark is one of the most talented media CEOs in the region, and has been recognised as such year after year."
Welcoming Heap back, Mark Patterson, Asia-Pacific CEO of GroupM added, "[Heap's] China and other major market and regional experience will be a tremendous asset to us. We were very clear and aligned he was our man from the word go."