"The Jewish world owes Israel Singer a tremendous debt of gratitude," it said.
Singer had maintained leadership of the policy council after stepping down as chairman of the WJC in 2006.
He had resigned the WJC chairmanship as part of an agreement with the New York attorney general's office following an investigation of the group's finances.
The investigation found no evidence of criminal wrongdoing but sharply criticised the world body's internal financial controls.
Under an agreement with the attorney general's office, the organisation committed to improving internal governance.
Singer also was required to repay what the attorney general's report described as "inappropriate disbursements" of more than $300,000. He also was barred from holding any role with authority over the group's finances.
He had occupied leadership positions in the WJC since 1986.
The WJC board also authorised a forensic audit of its Israeli affiliates.
The World Jewish Congress, headquartered in New York, was founded in 1936 with the aim of aiding the survival and growth of the Jewish people and their culture.