Exon, who will start his new role immediately, replaces James Murphy, who is leaving the agency to form a start-up with RKCR/Y&R's creative director, Ben Priest, and planning director, David Golding (Campaign, 22 June).
Following a meeting last week with senior WPP executives the trio will relinquish their responsibilities immediately and leave the agency within the next six weeks.
RKCR/Y&R will now also be looking for a replacement creative director and planning director.
The decision to promote Exon was made by Massimo Costa, Young & Rubicam's European chief, and Mark Roalfe, the chairman of RKCR/Y&R, who will now take over running the creative department until a creative director is found.
The move will also see Tony Harris, the international business director, become deputy chairman and Russell Hopson, the deputy managing director, becoming the managing director.