He was educated at the Rabbi Jacob Joseph School, the Talmudical Yeshiva of Philadelphia, the Telshe Yeshiva in Cleveland, and then at Yeshivas Torah Ore in Jerusalem, under the leadership of Rabbi Chaim Pinchus Scheinberg. He received four semichas: from Rabbi Serayah Deblitzky, a student of the Chazon Ish; Rabbi Ovadia Yosef, former Sephardi chief rabbi of Israel; Rabbi Betzalel Zolty, Ashkenazi chief rabbi of Jerusalem; and Rabbi Elazar Shach, a rosh yeshiva at the Ponevezh Yeshiva in Israel.
After leaving Torah Ore, Tropper accepted a position at the nascent Ohr Somayach institutions. After five years in Jerusalem teaching baalei teshuva, Tropper returned to the United States to become the educational director of Ohr Sameach, New York located in Yonkers and Monsey. In 1981, Tropper joined Rabbi Avrohom Gershon Tress zt"l in founding a new yeshiva for baalei teshuva, the Kol Yaakov Torah Center, and became its rosh yeshivah.
In 1995, Tropper founded a new outreach program called Horizons, focusing on educating and inspiring the unaffiliated to experience a Torah lifestyle. As its director, Tropper traveled the world lecturing and teaching. He has also written three books: a halachic work based on the decisions of his mentor Rabbi Scheinberg, a guide to the laws of yichud, a discussion of the prohibition of seclusion between men and women.
Eternal Jewish Family
Tropper founded the Eternal Jewish Family (EJF) project, which advocates more rigorous standards for conversion to Judaism, and assists intermarried families with conversion issues. Until 2009 he was the director and chairman of EJF's Rabbinic Committee. The organization was funded by billionaire Thomas Kaplan and Kaplan's nephew, Guma Aguiar, who donated at least $8 million to the project, according to IRS documents.
In 2006, The Jewish Week reported allegations that Tropper revoked a woman's conversion after learning that the woman "occasionally wore pants". Tropper denied this accusation, claiming the woman had in fact been breaking the Shabbat after her conversion, and that his role was confined to relaying this information to the appropriate authorities.
On December 14, 2009, the EJF announced that Tropper had resigned two days earlier, that he had been replaced as chairman of the Rabbinic Committee by Rabbi Elya Ber Wachtfogel, that Rabbi Chaim Blum would be taking over as interim director, and that Rabbi Reuven Feinstein, the chairman of the Halachic Committee, would take a more active role in overseeing the organization's activities. No reason was given for these changes. On December 18, 2009 Wachtfogel issued a letter denying that EJF is under his direction. The press release was then deleted from EJF's website. On December 20, EJF put out a new press release omitting all mention of Wachtfogel or the chairmanship of the Rabbinic Committee.
In October 2009, Tropper was sued by philanthropist Guma Aguiar for allegedly misappropriating funds given to him by Guma for charitable purposes. The lawsuit followed an altercation between Guma and Tropper in a Jerusalem hotel. Tropper claims that Aguiar threatened to throw him out a window. Aguiar's attorney denied any threat was made.
In early December 2009, recordings circulated on the internet that contained conversations between a man alleged to be Tropper and a woman whose conversion he was alleged to have been supervising, and which appeared to show that the two were involved in a sexual affair and in encouraging the woman to engage in sexual activities with others. Tropper released a statement through his attorney that admitted no wrongdoing and expressed regret for “what has appeared to be conduct not within our significant laws of modesty.”
On 14 February 2010 Tropper was to be summoned to a meeting in the Yeshiva Bais Mikroh of Monsey where the Rabbonim were to demand that Tropper resign all his posts and leave Monsey. Prior to the meeting, Tropper signed an agreement which stated “In not fulfilling the requirement of Shulchan Aruch that a leader be 'Pirko No’eh' (פרקו נאה), the undersigned is relinquishing his position.” Tropper also stated that he "released all rights and severs any connection he has to his former Yeshiva in Monsey and withdraws forthwith as a trustee of the organization." Tropper also stated his agreement to move out of Monsey within a few months.
Around a year later, Tropper published a halachic work with the written endorsement of Rabbi Boruch Dov Povarski of the Ponevezh Yeshiva who wishes Tropper success in disseminating Torah and mentions the saying of Chazal that one who influences many to become meritorious does not come to sin.
- "Kol Yaakov Torah Center-Faculty". Horizons.edu. Retrieved March 5, 2010.
- "Outreach Rabbi Resigns Amid Cloud Of Scandal". The Jewish Week. December 15, 2009. Retrieved Aug 4, 2013.
- Leslie Eaton, "Making it work; Speak No Evil? Quixote Had It Easy", New York Times, 31 January 1999
- Leib Tropper, Yichud: A Concise Guide, Shma Yisroel Publications, 1973.
- Allison Hoffman, "Among friends", Tablet Magazine, 19 January 2010
- EJF press release, 30 May 2008
- EJF press release, December 14, 2009
- "Change in Eternal Jewish leadership". The Eternal Jewish Family. Archived from the original on Dec 24, 2009. Retrieved December 20, 2010.
- "An Account of Events-Natan Slifkin". Zoo Torah. Retrieved March 5, 2010.
- Baruch Gordon. (8 October 2009). "Jewish Billionaire Sues Prominent US Rabbi". Arutz Sheva.
- Yair Ettinger, "U.S. rabbi involved in sex scandal led fight against Israel conversions", Haaretz, 24 December 2009
- Yuval Goren (9 September 2009). "U.S. rabbi accuses Beitar patron of threatening to defenestrate him". Haaretz.
- Reuven Blau and Melissa Klein (December 20, 2009). "Sex-tape rabbi tries to 'share' hottie". New York Post.
- Paul Berger, "Sex Tapes Rock the Orthodox", The Jewish Chronicle, 23 December 2009
- Allison Hoffman, Con Game, Tablet Magazine, 13 January 2010
- "Leib Tropper Resigns as Rosh Yeshiva of Kol Yaakov". Matzav.com. March 4, 2010. Archived from the original on Feb 6, 2010. Retrieved March 5, 2010.
- "Leib Tropper scandal finally put to rest". 5 Towns Jewish Times. February 16, 2010. Retrieved March 2, 2010.
- Pirkei Avot Chapter 5