Jenner & Block

Senior Energy Legal Executive Thomas S. O'Neill Rejoins Jenner & Block

CHICAGO – October 23, 2020 – Jenner & Block is pleased to announce that Thomas S. O’Neill, senior vice president and general counsel of Exelon Corporation, will rejoin the firm as a partner, effective January 1, 2021. Based in the firm’s Chicago office, Mr. O’Neill will be a member of the firm’s Energy Practice and its Litigation Department.

Since January 2017, Mr. O’Neill has served as the top legal advisor to Exelon’s board of directors and senior management, and he oversees the company's legal and corporate governance departments. He has a wide range of experience, having served in legal, business and strategic leadership roles across Exelon’s operating companies. He previously served as senior vice president, Energy and Regulatory Policy and general counsel at Exelon subsidiary ComEd. Before that, he held leadership roles within Exelon’s Generation business and served as senior vice president and chief operating officer of Exelon Transmission Company.

“Jenner & Block has a long tradition of lawyers who have returned to the firm following significant roles in-house and in public service, and we are excited to welcome Tom back,” said Katya Jestin, co-managing partner of Jenner & Block. “Tom is a highly respected lawyer whose commitment to excellence is evident in every aspect of his impressive career. We are looking forward to his leadership at the firm.”

Added Co-Managing Partner Randy Mehrberg: “I’ve had the great privilege of working closely with Tom when he was previously at Jenner & Block and while he was at Exelon. I know our clients will benefit from his deep knowledge, strategic insights and extraordinary breadth of experience. We are very fortunate that he has chosen to come home to Jenner & Block.” Mr. Mehrberg also serves as co-chair of the firm’s Energy Practice.

“As a young lawyer working at Jenner & Block, I developed a deep appreciation for its commitment to excellence, collaboration, diversity and inclusion, and pro bono and public service. These values have been with me throughout my career at Exelon and have shaped the way I practice law,” said Mr. O’Neill. “I am looking forward to returning to Jenner & Block and helping to expand the Energy Practice in particular, bringing my 19 years of corporate experience in a highly regulated and complex industry. It goes without saying that I’m very pleased to work alongside so many talented colleagues across offices.”

Throughout his career, Mr. O’Neill has been a dedicated pro bono advocate. His prior work at Jenner & Block has included several murder trials and a habeas case where he won outright reversal of a state juvenile murder conviction obtained through a coerced confession. He continued his pro bono advocacy at Exelon where the Law Department is nationally recognized as a pro bono leader. He also has established himself as a committed leader in Diversity Equity and Inclusion, including through his current service on the Board of the Leadership Council for Legal Diversity (LCLD)

Mr. O’Neill is an active member of the Association of General Counsel and the Chicago General Counsel Forum. He has served on the planning committees for corporate counsel forums at both Kellogg School of Management and the University of Chicago Law School. He also is active in the Chicago civic arena though his service on the boards of Christopher House, Legal Aid Chicago, and the American Ireland Fund.

A graduate of the University of Illinois at Urbana-Champaign, Mr. O’Neill received his law degree from the University of Notre Dame Law School.