She has been appearing before the international criminal courts and tribunals since 2005, acting as counsel in some of the leading cases in the field.

Kate is currently the Lead Counsel of Paul Rusesabagina, detained in Rwanda. She is also the Co-Counsel of Bosco Ntaganda before the International Criminal Court in The Hague. Between 2009 and 2018, she represented Jean-Pierre Bemba, former Vice-President of the Democratic Republic of the Congo, who was acquitted of all charges in June 2018. Kate is also a Legal Consultant to Hashim Thaçi, former President of Kosovo, before the Kosovo Specialist Chambers in The Hague.

In July 2018, Kate was appointed as Legal Consultant to the Independent International Fact-Finding Mission on Myanmar, established by the United Nations Human Rights Council in A/HRC/RES/34/22, and currently represents a group of Rohingya victims in Cox’s Bazar, Bangladesh.

Previously, she appeared before the United Nations International Criminal Tribunals for Rwanda and the former Yugoslavia, including as Lead Counsel to Minister Justin Mugenzi who was acquitted of all charges in 2013, Legal Assistant of General Gratien Kabiligi who was acquitted of all charges in 2008, and Co-Counsel of Radovan Karadžić, the former President of the Republika Srpška. She was also Co-Counsel to former Liberian President Charles Taylor before the Special Court for Sierra Leone.

Between 2007 and 2008, Kate was the Associate Legal Officer to Judge Mohamed Shahabuddeen in the Appeals Chamber of the United Nations International Criminal Tribunal for the former Yugoslavia. Kate was also a Legal Assistant for civil parties in the first case before the Extraordinary Chambers in Phnom Penh, Cambodia in 2009.

Kate holds an appointment as a Senior Legal Advisor with the Public International Law and Policy Group in Washington, D.C., and is a member of the Executive Committee of the International Criminal Court Bar Association, and a member of the Association of Defence Counsels practicing before the International Courts. Kate is published and teaches in international criminal law and procedure, and holds an LL.M (First) in International Law from Cambridge University. She lives in Geneva, Switzerland.