Felton joins as the head of channel planning, replacing the head of digital, John Hatfield, who is leaving the agency after 18 months in the role.
Hatfield is understood to be in final talks about taking another position at an undisclosed agency.
Rather than appointing a direct successor to Hatfield, Rapier has created a position that will see Felton take responsibility for the agency's new channel planning function, which will seek to position digital at its core.
Felton will develop multi-channel strategies for clients and use the agency's communication and data planning units to implement them. He will report to the strategy partner at Rapier, Bill Griffin.
Griffin said: "Ben has experience of creating strategies that pull all channels together and is a great hire for us. We saw a significant number of candidates for the role and Ben stood out from the start. He will be a fantastic catalyst as our model evolves."
In his former job, Felton was responsible for Agency.com's Ikea, Procter & Gamble, Dulux and Ladbrokes accounts as well as holding a position on the agency's management board.