Mr O'Sullivan was appointed Chief Executive of Optus in 2004. In this role he is responsible for all aspects of the performance and operations of Optus, Australia's second largest telecommunications company.

Under his direction, Optus has experienced five years of rapid growth. Over this period, revenues increased from A$6.6 billion to almost A$9 billion, whilst mobile customers grew from 5 million to more than 8 million. Mr O’Sullivan continues to focus on driving revenue and profitability through a commitment to innovation and customer value.

Mr O'Sullivan also has management responsibilities across the SingTel Group. From 2004-2009 he served on the Board of Bharti Airtel – India’s number one mobile communications company. He currently serves on the Board of Commissioners of Telkomsel, Indonesia’s largest mobile company, and is a member of the SingTel Group Management Committee.

Prior to his current role, Mr O’Sullivan held management positions including Chief Operating Officer and Managing Director of Optus Mobile.

He has previously held various international management roles including the Colonial Group and with the Royal Dutch Shell Group in Canada, the Middle East, Australia and the United Kingdom.

Mr O’Sullivan is a board member of the Australian Business and Community Network (ABCN), which engages businesses to positively impact the community. In addition, he is one of the founders of TERRiA, a network of companies advocating for more competition and level playing field in telecommunications.

Mr O'Sullivan has a B.A. (Mod) Economics, Trinity College, University of Dublin and is a graduate of the Harvard Business School’s Advanced Management Program.