He was a leader in the global campaign on behalf of Soviet Jewry and played a role in the lead-up to Israeli diplomatic relations between India and China.

[6] In 1962, Mr. Leibler engineered a public campaign which resulted in Australia becoming the first country in the world to raise the plight of Soviet Jewry at the United Nations.

[7] Before the collapse of the Communist bloc, Leibler made numerous visits to the Soviet Union and developed close associations with the leading Jewish dissidents and refuseniks, which he still maintained in Israel.

[10] Leibler's calls for a comprehensive independent audit" brought him into conflict with Singer and Edgar Bronfman, the WJC's longtime "president, chief benefactor, and guiding force.

"[11] In January 2005, Leibler resigned as WJC vice president, telling Haaretz that he "came to the conclusion that I cannot remain in an organization that requires me to give a stamp of approval to activities I deem inappropriate.

[18] A PricewaterhouseCoopers audit in 2006 submitted by the WJC to the AG's Office found that the financial scandal was "significantly broader than has been publicly known," with some $3 million unaccounted for from 1994 to 2004.

[21] Leibler called for a full external investigation and disclosure of massive misappropriations of funds at the Conference on Jewish Material Claims Against Germany (Claims Conference), citing allegations of incompetence, impropriety and cover-ups, the absence of an independent review board, bureaucratization and a domination by a small clique, along with a failure to "prioritize the needs of survivors, who are now elderly and many of whom are living in dire poverty.

[22] In response Claims Conference Julius Berman has accused Leibler of engaging "in irresponsible invective and baseless charges against an organization that for nearly 60 years has been the leading international advocate for the rights of Holocaust victims.

The biography detailed how he “acted unofficially under instructions from Avigur and Levanon, becoming a de facto operative for Israel on foreign affairs”[24] Leibler was a columnist for The Jerusalem Post.

In 2015, Leibler was awarded an honorary doctorate from Bar-Ilan University in recognition of “his tireless efforts to address the challenges facing the Jewish nation at every historic crossroad”.