Douglas (Doug) Levin is the brother of conservative radio host and author Mark Levin. An American serial entrepreneur and technologist, Levin began his professional career at Microsoft, where he served as a product evangelist from 1987 to 1995, contributing to the initial launch and subsequent releases of Microsoft Excel, as well as other marketing initiatives including the development of Microsoft's first volume licensing program. He later founded Black Duck Software, a company specializing in open-source software security, which was acquired by Synopsys in 2017. Levin has also worked as an adjunct faculty lecturer at business schools, sharing his expertise in technology and entrepreneurship.