Chairman , President and CEO , Graybar Graybar serves as both a wholesale technology business in areas such as networking hardware and a provider of supply chain management software . 415th on the Fortune 500 , the company has been led by CEO Kathleen Mazzarella since 2013 . She has been at the company since 1980 , having served in various VP , SVP and EVP roles along the way in areas including HR and sales and marketing . She studied for an MBA at Webster University .