From 1992 to 1998, Reiss worked as an associate at the international law firm of
Cleary Gottlieb Steen & Hamilton in New York City. He maintained an association with the firm until 1999. He is a member of the
New York State Bar Association, and was a certified mediator for the City of New York court system, and was a member of the Family and Divorce Mediation Council for New York. In 1998, Reiss assumed the position of Director of the Beth Din of America, a position he served until 2008, when he was appointed the Dean of Rabbi Isaac Elchonon Theological Seminary (RIETS). Reiss serves on the editorial board of
Tradition magazine. A frequent writer on a variety of topics relating to both Jewish and secular law, he has published widely in Jewish publications, as well as in the Wall Street Journal and New York Law Journal. In 2013, Reiss stepped down as Dean at
Yeshiva University and assumed the position of
Rosh Yeshiva.{{cite web|url=http://yucommentator.org/2013/03/rabbi-yona-reiss-to-leave-deanship-assume-rosh-yeshiva-position/|title=Rabbi Yona Reiss to Leave Deanship, Assume Rosh Yeshiva Position ==Personal life==