Professor Renwick has been an Honorary Professor at the ANU National Security College since 2025, having previously been a Distinguished Advisor at the College for some years and before that an Adjunct Professor for a decade.  He has a doctorate in constitutional law.  He was a Fulbright Scholar at the School of Advanced International Studies at Johns Hopkins University.

He practiced as a solicitor in private and government practice for a decade and in a wide range of matters as a barrister from 1996, and Senior Counsel from 2011.  He appeared in many constitutional law cases in the High Court of Australia and in inquiries in Australia and Papua New Guinea.

Since September 2025 he has been a judge of the Federal Circuit and Family Court of Australia Division 2, see: https://www.youtube.com/live/h4wn-umwRcM

He served as a Naval reservist for 30 years, concluding in mid-2026 as a Commodore in the Royal Australian Navy in the role of Deputy Judge Advocate General- Navy: Statutory appointments | Defence. He was Senior Counsel Assisting the IGADF Afghanistan Inquiry. In 2026, he edited the volume 40 Years On: the Judge Advocate General of the Australian Defence Force.

He was the 3rd Independent National Security Legislation Monitor, an agency head-level position. In that capacity he completed nine influential reports for the Prime Minister, Attorney-General and Parliamentary Joint Committee on Intelligence and Security on topics such as encryption, loss of citizenship and terrorism, and the prosecution and sentencing of children for terrorism.

He has received the Conspicuous Service Cross (CSC) for his naval service and Membership in the Order of Australia (AM) for his ‘significant service to the law and to national security.’

He is a Fellow of the Australian Academy of Law (FAAL) and the Royal Society of NSW (FRSN) and a Master of the Bench at Inner Temple, London.

His academic interests include: constitutional law, public law, national security and intelligence law, law of armed conflict and war crimes, Pacific security.