In 1993, while serving as the organization’s Philadelphia chapter president, he was elected national president.
The ZOA web site quotes the following from Klein's Encyclopaedia Judaica entry: "Klein revived a moribund Zionist Organization of America (ZOA) in the 1990s and made it one of the most out-spoken organizations on the American Jewish scene." 
He is a child of Holocaust survivors, born in a displaced persons camp in Gunzberg, Germany. He is an economist who served in the Nixon, Ford, and Carter Administrations. He has served as a biostatistician at UCLA School of Public Health and the Linus Pauling Institute of Science and Medicine in Palo Alto, Calif. He has been a lecturer in mathematics and statistics at Temple University.
His father was a Satmar chasid, an Orthodox Rabbi with semicha (religious ordination) from Rabbi Teitelbaum. Mr. Klein said in a Jewish Press interview  regarding his father that "In Europe he had a long beard and black hat and was a rosh yeshiva in his early 20s. But he disagreed with the Satmars on Israel. My father loved Israel, so obviously this was transmitted to me."
- http://www.zoa.org/sitedocuments/news_view.asp?newsID=834, which states in a footnote that "Its past presidents have included Supreme Court Justice Louis Brandeis."
- Popper, Nathaniel (2006-04-14). "ZOA Pressed by Former Officials Over Guard’s Pay – The Jewish Daily Forward". Forward.com. Retrieved 2010-08-12.
- "4819-ZOA Report FL08.p5" (PDF). Retrieved 2010-08-12.
- he said in an interview here  "We're not right wing. Everybody else is just very far left."
- example: speech described here
- "National President Morton A. Klein". ZOA.org. 2010-12-14. Retrieved 2010-12-14.
- "Morton Klein: Bibi Sent Wrong Message,Elliot Resnick, Jewish Press Staff Reporter". Jewishpress.com. 2009-06-24. Retrieved 2010-08-12.
- June 26, '09, p. 10
- ‘We want to expose the truth’: ZOA leader Morton Klein rallies support for Israel in meeting at Beth Tikvah in Naples, Naples News, Feb. 14, 2011