Proximity won the account after a four-way pitch, handled by the AAR, against VCCP Me, Balloon Dog and a consortium featuring the sister Omnicom agencies Rapp and Adam & Eve/DDB, which runs the John Lewis advertising account.
Incumbent Kitcatt Nohr Digitas decided not to repitch, and is thought to be focusing on the separate Waitrose CRM review.
Proximity will work across all direct marketing channels, supporting John Lewis’ marketing, database and email teams. It will work to grow the "my John Lewis" reward scheme which was soft launched in 2012.
The agency will also work on broader contact strategy, as well as launch marketing for John Lewis shop openings.
Chris Bates, the head of CRM and insight at John Lewis, said: "We have big ambitions for CRM, including growing my John Lewis, and are excited to invite Proximity to help us deliver our strategy."
Sharon Whale, the deputy chairman at Proximity, said: "John Lewis already enjoys a unique relationship with their customers and we feel privileged to have been chosen to partner with them to take this to the next level."