Varley joined Walker Media last October to lead the agency's flagship £90 million account. He replaced Ron Mudge who left to pursue other interests.
Mudge, a former director of Saatchi & Saatchi's in-house media operation, now runs the AA account at Manning Gottlieb OMD.
Varley has previously worked with the Walker Media founding partner Phil Georgiadis at WCRS in the 80s. Varley joined Walker Media from the screensaver media agency Oxigen, which he founded in 2000.
Christine Walker, a partner at Walker Media, said: "Charlie has already made a fantastic contribution to our founder client Dixons Stores Group. His past experiences offer us and Dixons great breadth and depth of media knowledge and insight as well as grounded commercial savvy."
Varley joins an existing managing partner team that includes Jon Horrocks, Nicki Hare and Nick Walker.
He said: "I've been fortunate to have worked over the past year with a fantastic client and a group of people who have a shared vision and passion for what we do."
Dixons Stores Group, comprising Dixons, Currys, The Link and PC World, is Walker Media's biggest-spending client. Walker Media recently picked up the £15 million media account for KFC.