O’Neil began his career at Intel Corporation, where he first developed his knowledge of the technology industry. He subsequently worked for McKinsey & Co. before moving to the automotive industry in the late
1980s, where he was President of Ertley MotorWorld, a dealer group based in Pennsylvania.
O’Neil went on to co-found and lead the development and rollout of CarMax, Inc. He was President and Chief Operating Officer of Greenlight.com, an online automotive sales website, from June 2000 through January 2001. He currently serves as a Director of DealerTire LLC, a privately held company.
O’Neil holds a B.S. in Industrial Engineering from Worcester Polytechnic Institute and an MBA from Harvard Business School.