Professor Gledhill's more than 30 years in the law, as both a practitioner and an academic, has spanned many aspects of law but has focused on criminal law and human rights law, particularly international human rights. As a barrister in London he largely worked as a criminal lawyer and representing the rights of detained people.
Although he had always contributed to academia through teaching, journal articles and books, he became a full-time academic when he and his family moved to New Zealand in the mid-2000s to a role at the University of Auckland.
Professor Gledhill joined AUT Law School in 2016, attracted in part by the focus of AUT on industry connections and the willingness to integrate "real world" examples into academic learning. He has been involved in the establishment of the Centre for Non-adversarial Justice and the Centre for Indigenous Rights and Law at AUT Law School.
He became a Barrister of the Inner Temple 1989.