Mark D. Ein, born on December 31, 1964, is a prominent American venture capitalist, sports team owner, and retired professional tennis player. Born in Chevy Chase, Maryland, he holds an economics degree from the University of Pennsylvania, as well as an MBA from the Harvard Business School. Prior to founding Venturehouse Group in 1999, Ein had worked with Goldman Sachs, Brentwood Associates, and The Carlyle Group.

Ein has been an avid tennis enthusiast and competed in several ATP tournaments. He is the current chairman of the DC Open tennis tournament and the founder of the Washington Kastles team, which participates in the World TeamTennis League (WTT). Apart from this, Ein also owns the Washington City Paper, the Washington Justice team in the Overwatch League (OWL), and holds a minority stake in the Washington Commanders team of the National Football League (NFL).

Ein is a member of several prestigious organizations, including the Federal City Council, the World Economic Forum, and the Gridiron Club. He has also been the chair of the President’s Export Council within the International Trade Administration since 2023. In 2013, Ein was honored by the Jefferson Awards Foundation for his “Outstanding Public Service in Professional Sports.”