
The move reinstates a position that has been vacant since Jane Ratcliffe left it to become the agency's chief executive last September.
Additionally, MediaCom group press director Claudine Collins and broadcast director Steve Bignell are set to take up joint investment roles that will expand their remits.
Upon taking the chief executive role, Ratcliffe initially dismissed the need to find a new managing director for the UK's biggest agency, favouring a management board divided into three units: commercial and finance, trading and business solutions.
Jowett was made head of the commercial unit, working alongside former deputy finance director Damien Glackin, but his promotion this week suggests a change of tack by the chief executive.
"I am keen to move MediaCom on," said Ratcliffe, "and after spending some time looking at the business have decided to put Dave in as my managing director. He will support me in running the agency on a day-to-day basis and allow me to spend more time with people and clients."
Jowett has been with the agency for nine years, joining as deputy broadcast director from Publicis Groupe's MediaVest. He was overlooked for MediaCom's head of broadcast role, which went to Steve Bignell in December 2005, but was made commercial director 18 months later.
His commercial expertise will be a strong asset in his new role, with Ratcliffe admitting the current economic climate makes it essential the agency "keeps a close eye on controlling costs".
He will look at how the agency interacts with its clients (which include Dell, E.ON, GSK and T-Mobile), while becoming MediaCom's "human face".
Jowett will work closely with MediaCom's operations team, which remains in place, and maintains his role as global account director for the Royal Bank of Scotland Group.