The Tunbridge Wells-based WFCA's chief executive, Michael Richards, was formerly the new-business director of Grey London and a one-time board director on its Mars account.
The appointment comes two months after Carpetright, then one of Grey's biggest domestic clients, took its full-service account out of the agency after failing to reach agreement over fees.
It also marks the first major success by WFCA in its efforts to extend its below-the-line work, including design, branding and packaging, into a full-service offering encompassing creative and media.
Caron Grant, Carpetright's head of marketing, said: We're delighted to be working with WFCA which, when pitching, proved it has a real grasp of retail advertising and demonstrated our account will be really looked after. Also, its strategic integrated offer gives us much greater scope to communicate our product offer."
WFCA will also handle Carpetright's new department store concession business.
Richards said: "I'm thrilled that we have won such a key client who, like us, is completely driven."