Sam d’Amato, chief product officer at Omnicom Media Group UK, has left after 17 years at the agency.
It is not clear what his next move is as a statement from the agency said that d’Amato will "explore new opportunities".
D'Amato joined the company as a graduate in 2002 at OMD UK and has held senior roles across the group including chief strategy officer at M2M, which closed its doors in 2016, and chief innovation officer at Hearts & Science UK. D’Amato became chief product officer two years ago.
Campaign has listed him in its top 10 media planners of the year three times. In 2018, he was in fourth place.
Dan Clays, chief executive of Omnicom Media Group UK, said: "Over the past 17 years, Sam has played an important role across Omnicom Media Group UK in a number of senior strategic roles.
"I have had the pleasure of working alongside Sam for several years – his energy and passion is infectious. And on behalf of everyone at OMG UK, I wish him the best of luck for the future and have no doubt he will be successful in whichever venture he turns his hand to."