O’Brien will relocate to Singapore from the UK to take charge of regional clients like Nokia, Adidas, Philips, Fox, Beiersdorf, BMW and ANZ Bank.
"Sean has a proven record of success, as an international player in the UK, Europe and the US, and during his five years in Asia. We are delighted that he has joined our team as we embark on the next phase of our growth in the region," said Waters.
O’Brien joins from his position as the regional EMEA and global account director at Omnicom Media Group (OMG) in London. He has lead the agency to win Google and Hewlett-Packard.
O’Brien has also spent four years as the managing director of M2M International and CEO of OMG Thailand. Aegis Media states that Thailand grew three fold under his leadership and gained accounts for Vodafone, Nissan, Apple, PepsiCo, GE, Fonterra, Intel and Tesco.