Professor Kate Diesfeld was employed as a staff attorney for Protection and Advocacy, Inc in Los Angeles representing people with developmental disabilities. She was the Legal Supervisor of Kent Law Clinic (Mental Health and Learning Disabilities) at the University of Kent at Canterbury in England. Also, she represented people before the Mental Health Review Tribunal in England.
She was Director of the National Centre for Health Law and Ethics at AUT University. At Te Piringa Faculty of Law at the University of Waikato, she was Co-editor of the Waikato Law Review, Associate Dean (Research) and taught Health Law, Torts, Dispute Resolution and Legal Ethics. Currently Adjunct Associate Professor at Te Piringa, and the Chair of AUT's Ethics Committee, Professor Diesfeld convenes the health law courses at AUT and supervises doctoral research on disability and health law.