She will be responsible for Jaywing's list portfolio, which includes Blooming Marvellous, The Sleepover Company, Designers Guild and Bambino Mio, as well as securing relationships with new lists and launching them to the market.
Stanford joins Jaywing from Evolution DM, where she was a business development consultant.
Prior to that she spent 12 years with Independent Direct Marketing where she held the role of sales director.
Stanford will be working closely with Shaun Crawford, consultant at Jaywing, on products including smartdecisions and smartlists.
Crawford said: "Karen brings with her a broad and detailed knowledge of lists and inserts management, and will be a strong addition to our already passionate and experienced team.
"Lists continue to be a major source of data for the industry, and providing our clients with such an experienced player will be key to delivering a continued solid service."