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John Warner

Senior PartnerOhio - Cleveland

Coleads the firm’s Global Energy and Materials Practice.

Having spent over 27 years with the firm, John is currently the coleader of the Global Energy and Materials Practice. He is also a member of the firm’s Senior Partner Review Committee and the Americas senior leadership team.

John focuses his client efforts on fundamentally improving the performance trajectory of leading-edge companies. Specific areas include corporate strategy and finance, marketing and sales, operations, organization-efficiency effectiveness, and change management.

John has a passion for Ohio and has led many high-impact initiatives with the business community on economic development, healthcare, and education. He is currently co‑chair of the Ohio Business Roundtable.

Prior to McKinsey, John was a financial analyst at a multinational conglomerate, where he was a graduate of the company’s financial-management program. In addition to his MBA from Harvard Business School, John has a BA in Economics from the College of William and Mary, and a general course degree from the London School of Economics.

Published work

The making of a megadeal: Howard Ungerleider on the merger of Dow and DuPont,” McKinsey & Company, September 2021

Past experience

General Electric
Financial analyst


Harvard Business School

College of William & Mary
BA, economics