Founded in 2010, Media iQ is headquartered in the UK and has a roster of more than 400 clients.
Easterbrook’s arrival is said to reinforce the ambitions of Media iQ to transform the way clients look at data informed marketing.
Paul Silver, chief strategy officer at Media iQ, said: "Stewart needs no introduction. He brings with him second-to-none experience and leadership in the media industry from over the last 20 years. To bring on board someone with his experience and expertise represents how far we have come in just under four years."
Easterbrook was most recently executive director of performance and digital development for SMG EMEA. Prior to this, he was chief executive of SMG for five years.