Chris Martin, senior comms manager (property acquisitions) at Asda Wal-Mart, is joining the agency in early July. He will also join the consultancy's management board.
He replaces Linda Griffin, who moved on to handle pan-European policy comms at Facebook.
The Communication Group's chair Maureen Sutherland Smith said: 'We are delighted to be welcoming Chris. He will add significant value to this important part of our business.'
Martin has worked at Asda Wal-Mart since 2010.