The appointment is the first for DDB's new chairman and chief executive, Martin O'Halloran, who took up the role last week following the exit of Nick Cleaver.
Originally from Australia, Eastwood has been in America for two years where he was the executive creative director of M&C Saatchi, before moving to Y&R.
Before this, Eastwood was the executive creative director at M&C Saatchi in London.