Lesley Klaff taught law in the United States for seven years before taking up her post at Sheffield Hallam University in 1993. She was also Affiliate Professor of Law at Haifa University, 2007 – 12. Her research is in the field of contemporary anti-Semitism. She is the Associate Editor for the Journal for the Study of Antisemitism, an international, peer-reviewed journal and serves on the Academic Advisory Board of the Louis D. Brandeis Center for Human Rights under Law, a non-profit civil and human rights organisation in Washington DC established to combat anti-Semitism in higher education through research, education and advocacy.

Lesley also serves on the Advisory Board of the Berlin International Center for the Study of Antisemitism, a non-profit organisation dedicated to fighting anti-Semitism through research. She is a member of UK Lawyers for Israel (UKLFI), an NGO set up to provide pro-bono legal advice, assistance and representation to victims of anti-Semitism. Her responsibilities include giving advice to university students who experience anti-Semitic harassment on campus.

She appeared in the 2014 documentary on campus anti-Semitism, “Crossing the Line UK” produced by Raphael Shore and directed by Wayne Copping. She was interviewed on footballer Niclas Anelka’s use of the quenelle gesture for the Eurosport channel, broadcast on January 25th, 2014. Lesley appeared as a panel member at the Annual Liberal Democrat Conference in Glasgow, on September 16th, 2013, where she spoke alongside Alistair Carmichael MP, Maajid Naawaz of the Quilliam Foundation, and Mark Gardner of the Community Security Trust, on the topic of anti-Semitic discourse. She was also a witness for the claimant in Fraser v The University and Collegenion (March 22nd, 2013), which alleged institutional anti-Semitism against the UCU.  Lesley participated in a keynote panel at The Battle of Ideas Festival 2014 on the topic of “After Gaza: the return of antisemitism?” alongside Hugo Rifkind, David Mellor QC and Professor Frank Furedi and participated in a Roundtable Discussion on Campus Antisemitism, chaired by Claire Fox, with university vice-chancellors, at the House of Lords in October, 2014. Lesley is currently co-organising an international Antisemitism Colloquium at Bristol University, September 16 -18.  She is also guest editing a special University of Vienna Conference issue of the Journal for the Study of Antisemitism on the topic of “Antisemitism in the Shadow of the Holocaust, which is due for publication in December 2015.