Greenberg launched his first company, International Communications Associates, in the field of information technology of information processing. In 1966, Greenberg developed and got patents on an electronic device for compressed speech, which speeds up the reproduction of words from recordings without distorting any sound. In 1966 Greenberg was named one of the ten "Outstanding Young Men" of America by the
United States Junior Chamber. That spring, Greenberg was also one of seventeen young Americans selected to be White House Fellows in the
Lyndon Johnson administration. While serving as a Fellow, Greenberg formed a close friendship with
David Rockefeller, who had helped found the Program and became Greenberg's mentor. In 1968, with $2 million raised from Wall Street financial institutions, Greenberg launched EDP (Electronic Data Processing), a systems-analysis company headquartered in Washington, DC. During these years, Greenberg was still perfecting the speech-compression machine he had been working on for almost a decade. The final design, patented in 1969, was one of the earliest methods for time-scale modification of speech. Greenberg licensed the device to Sony, General Electric, Matsushita, and other manufacturers of audio equipment. As a member of the board of governors of
Ford's Theatre, Greenberg played a role in the renovation and 1968 reopening of the site of
Abraham Lincoln's assassination. The following year Harper & Row published Greenberg's analysis of Executive Branch decision-making,
The Presidential Advisory System, co-edited with Thomas E. Cronin. In May 1974, the
Young Presidents' Organization named Greenberg its first Man of the Year while he was serving on the board of
Ben-Gurion University of the Negev and as a director of the
Capital Centre (Landover, Maryland), and as a partner of the
Washington Capitals. Greenberg added a second sports venue to his real-estate interests in 1976 when he purchased the
Richfield Coliseum, home of the
Cleveland Cavaliers. In 1983, Greenberg founded T.E.I. Industries. As a past director of the National Committee on U.S.-China Relations and a longstanding member of the
Council on Foreign Relations, Greenberg was a founding director of the "American Agenda: A Report to the Forty-First President of the United States," George H. W. Bush, chaired by Presidents Carter and Ford. In 1994, Bill Clinton appointed Greenberg to the
National Science Board, and in 1996, he became chairman of the federal Rural Healthcare Corporation created by Congress. ==Greenberg Prize==