Weedon, a managing partner of PHD, has been hired as Maxus looks to grow its UK offering following its rebranding in January.
At PHD Weedon has been responsible for running one of its client divisions, heading management of accounts including Sainsbury’s, Cadbury and the AA.
Weedon, who joined PHD in 2003 having previously run a design and marketing agency in New Zealand, will head a management structure at Maxus which also includes joint managing director Tim Irwin and James Jennings.
Irwin and Jennings will report to Weedon while Weedon will report into both Kelly Clark, the global chief executive of Maxus, and Nick Theakstone, the UK chief executive of WPP's media unit Group M.
Clark said: "This is an exciting day for Maxus - Lindsay is a smart, passionate and ambitious leader and we're thrilled to have someone with her talent and experience to help drive Maxus to a new level."
Theakstone said that Weedon's experience of "delivering integrated media solutions" for clients was a key reason for her appointment.
He added: "Lindsay has proven she can deliver outstanding results for some of the most sophisticated clients in the UK."