Many of those who studied in Merrion Street built their careers outside Ireland. One of the most notable of these is David O'Reilly, who went on to become chairman and chief executive officer of Chevron Corporation.
A native of Dublin, David O'Reilly earned his bachelor's degree in chemical engineering from UCD in 1968. Upon graduation, he took up a position with Chevron Research in the United States as a process engineer. Over the course of his career with Chevron, O'Reilly served in positions of increasing seniority, responsible at various stages for the corporation's strategic planning, US refining and worldwide exploration and production. He was appointed chairman and chief executive officer of Chevron Corporation on 1 January 2000, a position he held until his retirement ten years later. He is now chairman of the National Petroleum Council in the United States and a director of Bechtel Group and Saudi Aramco.
David O'Reilly maintains his association with UCD Engineering as adjunct professor of chemical and bioprocess engineering and chair of the university's Energy Advisory Board. He received an honorary D.Sc. degree from UCD in June 2002.