Singer served as Secretary-General of the World Jewish Congress (WJC) from 1986 until 2001. In October 2001, he was elected chairman of the Governing Board WJC. In 2002, he was elected president of the Conference on Jewish Material Claims against Germany, the "Claims Conference". In June 2002, he was elected chairman of the International Jewish Committee for Interreligious Consultations (IJCIC). On January 11, 2005, Singer resigned as Secretary General of the WJC at its Plenary Meeting in Brussels. A replacement was elected, and Singer was elected to the Chair of the WJC Policy Committee.
During Singer's term at WJC, he was active in exposing and publicizing the Nazi past of United Nations Secretary General Kurt Waldheim.
Singer also acted as vice-chairman of the Yad Vashem Council.
WJC Policy Council
In early 2006, the WJC reached a settlement with the New York State Attorney General's office regarding its finances. Singer described the filings as baseless "nuisance suit[s]" and reiterated his innocence.
↑Second Generation Voices: Reflections by Children of Holocaust Survivors and Perpetrators. Religion, theology, and the Holocaust. Alan L. Berger, Naomi Berger (eds.) (1sted.). Syracuse, N.Y: Syracuse University Press. 2001. p.222. ISBN978-0-8156-2884-2.{{cite book}}: CS1 maint: others (link)