David McClanahan began his career with CenterPoint Energy in 1972 and held positions in information systems, accounting and treasury before being named assistant secretary and assistant treasurer in 1983.

He was named vice president and comptroller of Houston Industries, Incorporated, predecessor to CenterPoint Energy, in 1986. McClanahan was named senior vice president and CFO of KBLCOM, the company's cable television subsidiary in 1990, holding that position until 1993 when he was named group vice president of finance and regulatory relations, and later executive vice president of energy delivery and customer service for Houston Lighting & Power Company. He was named president and COO of Houston Lighting & Power in 1997. Two years later, he became president and COO of Reliant Energy Regulated Group and served as vice chairman of Reliant Energy, positions he held until assuming his current position.

McClanahan serves on the boards of the Interstate National Gas Association of America, the American Gas Association, the Houston Chapter of the Financial Executives Institute, Junior Achievement of Southeast Texas and the Gulf Coast Regional Blood Center. He is a member of the American Institute of Certified Public Accountants, Texas Society of Certified Public Accountants and Houston Chapter of Certified Public Accountants. He is former chairman of the Board of Regents of the University of St. Thomas.

McClanahan received his bachelor's degree from The University of Texas and his master's of business administration degree from the University of Houston. He is a certified public accountant.