Murray will take up the role of planner, working across all of the agency's accounts, although he will not initially take equity in the business.
While at BBH, he worked on accounts including Levi's, Vodafone and Warburton's, and also worked closely with Kevin Brown, BBH's director of engagement planning.
In a similar vein, Murray will work with the Adam & Eve founding partner Jon Forsyth to develop the agency's comms planning capability and set up its planning department.
David Golding, a partner at the agency, said: "David has a brilliant pedigree, and his open-minded and creative way of working with media planning is invaluable." Murray added: "I loved my time at BBH, but the chance to build something from scratch was too much for me to turn down."