Geoff graduated from Newcastle University in 1983 and completed his training as a General Physician with specific interest in Respiratory medicine and Pulmonary Physiology at the Royal North Shore Hospital, Royal Newcastle Hospital and Sir Charles Gairdner Hospital in Perth.

He worked as a General and Respiratory Physician at the John Hunter and Belmont Hospitals from 1991 and in private practice as a Respiratory Physician from 1991 to 2025.

From 2025 he no longer performs consultations for private general respiratory problems and his private practice is limited to occupational lung disease and respiratory medicolegal consultations. 

He established, and was the Director of the Newcastle Pulmonary Function Laboratory from 1994 to 2025.

He currently works at the John Hunter as a Respiratory Physician. He is appointed as an Associate Senior Clinical Lecturer in the Faculty of Health at the University of Newcastle and is involved in the training of medical students and Resident medical officers and Registrars within the Hunter New England Health service.

In association with his colleagues, he runs the Interstitial Lung Disease Service at the John Hunter Hospital. He was  a member of the Medical Assessment Panel of  the Dust Diseases Authority of NSW from Jan 2014 to Dec 2020 and since 2023 is a deputy chairman of the Medical Assessment Panel.