Board of Directors

Philip W. Knisely 

Chairman of the Board of Directors, Atkore International

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Mr. Knisely is an operating advisor to Clayton, Dubilier & Rice and has served for over 20 years as a senior executive in the diversified industrials category. Mr. Knisely spent a decade as Executive Vice President and Corporate Officer of Danaher Corporation, where he was responsible for businesses totaling more than $4 billion. Prior to Danaher, Mr. Knisely co-founded Colfax Corporation, a designer, manufacturer, and distributer of fluid handling products, serving as President and Chief Executive Officer. Previously, Mr. Knisely was President and Chief Executive Officer of AMF Industries, a privately held diversified manufacturer, and spent ten years at Emerson Electric. He serves on the Board of Trustees of the Darden School Foundation at the University of Virginia, where he received his M.B.A. Mr. Knisely was also a GM Fellowship Scholar at General Motors Institute, where he earned a B.S. in industrial engineering.

James G. Berges 

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Mr. Berges is a partner at Clayton, Dubilier & Rice and has been with the firm since 2006. Previously, he served as vice chairman and president at Emerson Electric Co., where he led corporate growth and development activities and was responsible for the company’s motors and appliance components, industrial automation, and network power businesses. Previously, he worked at General Electric Company. Mr. Berges is chairman of Hussmann International, Sally Beauty Holdings, Inc. and HD Supply, Inc. and serves on the boards of Atkore International, NCI Building Systems, Inc. and PPG Industries, Inc. He is a past chairman of the National Association of Manufacturers and also received a presidential appointment to the Advisory Committee for Trade Policy and Negotiations in March 2005. He holds a B.S. in electrical engineering from the University of Notre Dame.

Nathan K. Sleeper 

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Nathan K. Sleeper is a partner at Clayton, Dubilier & Rice and has been with the firm for eleven years. He led CD&R’s investments in Atkore International, Hussmann International and NCI Building Systems and serves as a director at Atkore, Culligan, HD Supply, Hertz, Hussmann, NCI and U.S. Foodservice. Previously, Mr. Sleeper played an integral role in the firm’s investments in Alliant, Brakes and Jafra. Prior to CD&R, he worked in the investment banking division of Goldman, Sachs & Co. and at investment firm Tiger Management. Mr. Sleeper holds a B.A. from Williams College and an M.B.A. from Harvard Business School.

A. Mark Zeffiro 

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Mr. Zeffiro is president and chief executive officer at Horizon Global, a designer, manufacturer and distributor of custom-engineered towing, trailering, cargo management and accessories serving the automotive aftermarket, retail, and original equipment channels.  Horizon Global became a stand-alone, publicly traded company in June 2015 as part of the spin-off of TriMas’ Cequent businesses, where Mr. Zeffiro held the position of group president.  Prior to that, Mr. Zeffiro was the chief financial officer responsible for investor relations, financial planning, business analysis, treasury, tax and systems and technology.  Before joining TriMas, Mr. Zeffiro spent four years at Black and Decker Corporation as vice president of Finance for Global Consumer Products Group and vice president of Finance for the U.S. Consumer Products Group.  Mr. Zeffiro began his career at General Electric Company, where he spent 15 years in roles of progressive responsibility, including chief financial officer of the Americas and Global Imaging Equipment division within the GE Medical Systems Group. Mr. Zeffiro earned a Bachelor of Science in Quantitative Analytics from Bentley College.

J.L. Zrebiec 

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Mr. Zrebiec is a principal at Clayton, Dubilier & Rice and has been with the firm since 2004. He has played a key role in the execution of several of the firm’s transactions, including the investments in Atkore International, Hussmann, NCI, Rexel and Hertz. He is a director of Atkore, Hussmann and NCI. Previously, he worked in the investment banking division at Goldman, Sachs & Co. Mr. Zrebiec graduated from the University of Pennsylvania with a B.S. in economics and earned an M.B.A. from Columbia University.

John P. Williamson 

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John P. Williamson joined Atkore International as President and Chief Executive Officer on June 1, 2011. Mr. Williamson previously spent six years with ITT Corporation, most recently as President of the Water & Wastewater Division. Prior to that, he was President of the Residential and Commercial Water Division and ITT Corporate Vice President and Director for Operational Excellence. Prior to ITT, Mr. Williamson was employed for more than 17 years within several operating divisions of Danaher Corporation. Until 2005, Mr. Williamson was Senior Vice President of Global Operations for Fluke Corporation. Mr. Williamson also served as President of Jennings Technology Corporation. Additionally, he held leadership and management positions at Veeder-Root Company, Danaher Controls, Dynapar and Disc Instruments. Mr. Williamson began his career with Connector Technology, Inc. in 1981. Mr. Williamson earned a B.A. degree in Business Administration from California State University Fullerton and holds a Certificate in Strategic Marketing Management from Harvard Business School.