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Denis P. O'Brien

Advisor to the CEO, Exelon Corporation


Denis Obrien Exelon Corporation Advisor

​A 36-year veteran of Exelon and PECO, Denis P. O’Brien serves as Advisor to the CEO. In that capacity, O’Brien is responsible for applying his extensive industry experience to a variety of challenges and ensuring Exelon is well-positioned for the future.


Professional History


O’Brien previously served as CEO of Exelon Utilities, which provide safe, reliable, affordable and clean electricity and natural gas to about 22 million people across the District of Columbia, Delaware, Illinois, Maryland, New Jersey and Pennsylvania. Together, Atlantic City Electric, Baltimore Gas & Electric (BGE), Commonwealth Edison Company (ComEd), Delmarva, PECO and Pepco make up the nation’s largest electric and natural gas distribution company. O’Brien led efforts to realize the outstanding operation excellence and improvements all Exelon’s utilities have achieved.

Prior to his role as CEO of Exelon Utilities, O’Brien served as executive vice president of Exelon and CEO of Philadelphia-based PECO, Pennsylvania’s largest electric and natural gas utility, advancing PECO’s operations and reliability, customer satisfaction and financial performance.

He was appointed as president for PECO in 2003 and was named president and CEO in 2007. He has more than 30 years of utility experience in engineering, operations, strategic planning and executive management. Prior to becoming CEO of PECO, O’Brien served as executive vice president and as vice president for operations with responsibility for engineering, construction, maintenance and emergency response for the company’s natural gas and electric distribution systems. His special assignments have included strategic planning on mergers and acquisitions, development of the company’s deregulation strategy and organizational redesigns to improve performance. PECO has been highly recognized for leading employee safety, diversity, economic development and environmental programs.

Civic Involvement

O’Brien has served as the chairman of the board of the Greater Philadelphia Chamber of Commerce, the Electric Power Research Institute (EPRI), the Pennsylvania Business Council and the Energy Association of Pennsylvania.  His other civic and industry board appointments include Independence Blue Cross, the Franklin Institute and Drexel University.  He previously served on the board of directors for the American Gas Association (AGA), the Pennsylvania Economy League, YMCA of Greater Philadelphia and WHYY, Inc.​



O'Brien holds a bachelor's degree in industrial engineering from Rutgers University and earned a master's degree in business from Drexel University.



O'Brien and his wife, Carolyn, have three children.