Board of Directors

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Philip W. Knisely

Chairman of the Board of Directors, Atkore International

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

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.

Jeri L. Isbell

Ms. Isbell is Vice President-Human Resources and Corporate Communications at Lexmark International, Inc., a leading developer, manufacturer, and supplier of printing, imaging, device management, managed print services, document workflow and business process, and content management solutions, a position she has held since 2003. During her 24-year tenure at Lexmark, she also held a variety of senior roles, including Vice President of Compensation and Benefits, Vice President of Finance and Division Chief Financial Officer, and U.S. Controller. Ms. Isbell began her career at IBM. She currently serves on the Kentucky Chamber Board of Directors, The Nature Conservancy (Kentucky Chapter), and the Graduate Degrees for Minorities in Engineering and Science (GEM) Consortium. She was the 2012 Chairperson of the Lexington, Kentucky Chamber of Commerce Board of Directors. Ms. Isbell earned a Masters of Business Administration from Xavier University, a Bachelor of Business Administration in Accounting from Eastern Kentucky University, and is a Certified Public Accountant.

Scott H. Muse

Mr. Muse recently retired after a 35-year career in the lighting and electrical industry. He served as a president in the lighting industry for 21 years, with the most recent role as President of Hubbell Lighting and Group Vice President of Hubbell Incorporated, one of the largest lighting fixtures and controls manufacturers in North America. Prior to that, he was President of Progress Lighting then President and CEO of Lighting Corporation of America. Earlier in his career, Mr. Muse held management positions with Thomas Industries, American Electric and Thomas & Betts which included sales, marketing, operations and general management. He maintained active leadership participation in industry associations which included serving on the Lighting CEO Board of the National Electrical Manufacturers Association, Board of Governors of the American Lighting Association, Manufacturers Advisory Council of the National Association of Electrical Distributors, in addition to the Business School Advisory Council of Georgia Southern University. Mr. Muse currently serves on the boards of the Peace Center for the Performing Arts in Greenville, S.C., The Children’s Museum in Greenville, S.C., YMCA in Spartanburg, S.C. and Greenville Technical College Foundation Capital Campaign. Mr. Muse earned a Bachelor of Science in Business Administration from Georgia Southern University which later honored him as the Business School alumnus of the year.

Nathan K. Sleeper

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.

William VanArsdale

Mr. VanArsdale recently retired after a 42-year career with leading diversified industrial manufacturers. For the past 11 years, he has served as Group President for the Hydraulics, Filtration and Golf Grip Group, a leading manufacturer of systems and components for mobile and industrial applications, within Eaton Corporation. Prior to that, he was Operations Vice President-Global Sales and Service for the Cutler-Hammer business of Eaton, and then he was named President, Electrical Components Operation for the same business. Previously, Mr. VanArsdale spent 12 years at Rockwell Automation serving as Vice President-Marketing for Control and Information Group and Director-Marketing for Sensing products. He began his career at Cutler-Hammer as a Sales Engineer, with progression to Product Line Manager, and Marketing Manager. Mr. VanArsdale earned a Bachelor of Science in Electrical Engineering from Villanova University and completed the Wharton Executive Education program for Finance and the Harvard Business School Executive Education program for Strategic Planning.

John P. Williamson

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.

A. Mark Zeffiro

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

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.


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Atkore International
16100 South Lathrop Avenue
Harvey, IL 60426
Toll free: 800-882-5543
Local: 708-339-1610