Harry Greenstein was a "civil servant in the finest meaning of the phrase." A young participant in the Young Men's Hebrew Association, he later became the Baltimore chapter's president. In 1928, he left his private law practice to serve as the executive director of the Associated Joint Charities in Baltimore. Twenty years later, he served as the Special Advisor on Jewish Affairs to General Lucien D. Clay in Germany and Austria, helping to resettle over 60,000 Jewish refugees. As well, he laid significant groundwork for Germany to pay reparations to the State of Israel. Following this work overseas, Greenstein returned to Baltimore, where he spent the last twenty-five years of his life as the executive director of the Associated Joint Charities and then the Executive Vice Chairman of the Legacy and Endowment program. His life was one dedicated to Jewish communal service around the world.