Rabbi Greenberg has helped found and run several leading organizations that have made major contributions to the Jewish world. Reflecting on his impact in this arena, he notes, “A significant part of my life’s work has been building new institutions that I believe are needed for Jewish continuity and for nurturing Jewish identity in the open society of the U.S.”

• Taglit—Birthright Israel
  In  2000, Rabbi Greenberg helped forge a partnership of philanthropists, Jewish federations, and the government of Israel to create the Birthright program, offering a free, organized educational trip to Israel to qualifying American Jews between the ages of 18 to 26.
• United States Holocaust Memorial Museum
  Rabbi Greenberg served as chairman of the United States Holocaust Memorial Museum from 2000 to 2002. Dedicated in 1993, the museum was founded as a living memorial to the Holocaust, inspiring citizens and leaders worldwide to confront hatred, promote human dignity, and prevent genocide.
• Jewish Life Network
  Rabbi Greenberg was founding president of the Jewish Life Network from 1997 to 2007. The goal of the Jewish Life Network, now called The Steinhardt Foundation for Jewish Life, is to strengthen and transform American Jewish life so that it may flourish in a fully integrated, free society. Its initiatives reach out to all Jews, with an emphasis on those who are on the margins of Jewish life. Jewish Life Network in turn founded PEJE and Birthright Israel, listed separately here, as well as several other initiatives including: Makor, a nightclub/music performance space to reach out to those in their twenties and thirties; Synagogue Transformation and Renewal (STAR); and the Jewish Early Childhood Educational Initiative (JECEI).
• Partnership for Excellence in Jewish Education (PEJE)
  In 1997 Rabbi Greenberg and philanthropist Michael Steinhardt recruited a dozen philanthropists and organizations to launch PEJE, an institution dedicated to impacting the field of Jewish education.
• President’s Commission on the Holocaust
  Founded in 1978 by President Jimmy Carter, the President's Commission was charged with making recommendations for a suitable memorial to the victims of the Holocaust. Rabbi Greenberg was director in 1979 when the Commission submitted its report to the President, and continued in this role until 1980. Rabbi Greenberg also worked with Zachor: Holocaust Memorial Center, which preceded and led to the establishment of the Commission.
• The National Jewish Center for Learning and Leadership (CLAL)
  Rabbi Greenberg is president emeritus of CLAL, having served as its founding president from 1974 through 1997. CLAL, a leader in religious pluralism, is a leadership training institute, think tank, and resource center that links Jewish wisdom with innovative scholarship to deepen civic and spiritual participation in American life.
• Association for Jewish Studies (AJS )
  Founded in 1969, the primary mission of the Association for Jewish Studies (AJS) is to promote, facilitate, and improve teaching and research in Jewish Studies at colleges, universities, and other institutions of higher learning. Rabbi Greenberg was a member of the founding group of AJS.
• Salantar Akiba Riverdale Academy (SAR)
  Rabbi Greenberg was founder and initial dean (1967–68) of the SAR Academy in Riverdale, New York, a cutting-edge modern Orthodox yeshiva educating students from pre-school through high school.
• Riverdale Jewish Center
  Rabbi Greenberg served as rabbi of the Riverdale Jewish Center Synagogue from 1965 to 1972.
• Academic posts
  Rabbi Greenberg spent a good deal of his career in the academy, including at these universities:
  • City College, City University of New York
    He was professor in the Department of Jewish Studies from 1972 to 1979 and served as chairman from 1972 to 1976.
  • Yeshiva University
    He chaired the Department of History and served as associate professor from 1964 to 1972 and assistant professor from 1959 to 1964.
• Student Struggle for Soviet Jewry (SSSJ)
  In 1964 Rabbi Greenberg helped establish SSSJ, the first American national movement to free Russian Jews. In operation from 1964–1991, this organization helped generate the wave of international public pressure which ultimately forced open the gates of the Kremlin to mass emigration and the release of refuseniks and Prisoners of Conscience.
• Yavneh: The National Jewish Religious Students Association
  Greenberg helped establish Yavneh in 1960 as an independent, Orthodox, student-run collegiate organization. Widely credited with having a revolutionary impact on Orthodox Jewish life, Yavneh was operational until 1981. It was committed to helping students on university campuses by focusing on Jewish education, Jewish observance, communication, Jewish unity, and community. This link is to the book The Greening of American Orthodox Judaism: Yavneh in the 1960s by Benny Kraut and Jonathan Sarna (Wayne State University Press, 2011).

Additional

• J.J. Greenberg Memorial Website 
  This website is dedicated to the memory of J.J. Greenberg, who died as a result of a bicycle accident in Israel in September 2002, at the age of thirty-six. J.J., the son of Rabbi Greenberg and his wife, Blu, was the executive director of Jewish Life Network and often collaborated with his father..
• Jewish Sages of Today 
  Both Rabbi Greenberg and his wife, Blu, a leader in Orthodox feminism, are featured in sections on this website, which includes examples of their work, interviews with them, and more.