Lawson is to be based in London and will report to Kelly Clark, chief executive of Maxus Global, and Lindsay Weedon, CEO of Maxus UK.
He will join other recent hires at the expanding WPP agency, who include Alan Hodge, Maxus Global group head of trading, and Adrian Carpenter, UK investment director.
Clark said: "This is a new position for our agency and we've given [Martin] a very broad brief that I am confident he has the skills and personality to accomplish."
Lawson's responsibilities will include new business and the development of techniques, tools, and consulting solutions for the agency’s global network and its clients, which include Mercedes-Benz, UPS and the recently obtained US brief for hair and beauty client Alberto Culver and UK business for telecoms company BT.
Lawson will work closely with Nick Vale, the agency's global planning director, as well as client leaders and data analysts in key Maxus offices around the world.
Lawson said: "Maxus is an agency on the move and is clearly making headway in markets around the world. I'm very excited to be a part of this rapidly growing network and I look forward to making a contribution to our future success."
Lawson was previously head of insight at i-level, the digital media agency that went into administration in May. Prior to that Lawson worked as director of analytics at media agency PHD in London.