Professor Sir Montgomery has chaired the Advisory Committee on Clinical Excellence Awards, the Human Genetics Commission and the UK Clinical Research Collaboration Working Party on a Strategy for Brain Tissue Banking. He was a member of the Committee on the Ethical Aspects of Pandemic Influenza and the Organ Donation Taskforce (for its work on presumed consent in 2008) and a member of the Medical Ethics Committee of the British Medical Association from 2003 to 2008.

He served on NHS boards in Hampshire and the Isle of Wight for over twenty years. His most significant research contributions lie in the field of Health Care Law.