During her presidency, she presided over the creation of Hadassah International, which has branches in more than 30 countries.
Lewis, an outspoken advocate of Israel and the Jewish people, was also a past chairwoman of the World Jewish Congress-American section and headed its Global Commission on Anti-Semitism for the United States and Canada. She was a lifetime member of the board of governors of Hebrew University and a member of the executive and national board of the American Zionist Federation.
In addition, she was involved in the Jewish National Fund, the United Israel Appeal, the World Zionist Organization, the National Jewish Community Relations Advisory Council and the U.S. Holocaust Commission, among other groups.