Norman will take over the role on 31 March from Marc Goldstein, who will be retiring after two years heading GroupM North America.
Management responsibilities will be shared between Norman and Rino Scanzoni, chief investment officer at GroupM, which is the pooled media buying operation of WPP's four media networks MediaCom, Mindshare, Mediaedge:cia and Maxus.
Irwin Gotlieb, global chief executive of GroupM, said: "Rob's background, combined with the direction the media marketplace is headed, makes him the perfect choice to lead GroupM in this region in the coming decade."
Norman created the new media division of CIA in 1994 and went on to become managing director of Mediaedge:cia's digital division Outrider, then chairman of Mediaedge:cia UK in 2003.
He relocated to the US in 2004 to develop MEC's worldwide offering, later becoming worldwide chief executive of newly created Mediaedge:cia Interaction and in 2006 worldwide chief executive of GroupM Interaction.
Last November he estimated that brands will boost their online spend to upwards of 20% of their media budgets by 2015.