John was appointed clinical immunologist and immunopathologist to an earlier iteration of the Canterbury District Health Board- (CDHB) in 1989 after completing specialist training at Flinders Medical Centre Adelaide. For over 25 years he worked in general medicine as well as specialist immunology. He has clinical and laboratory experience in his specialist field encompassing organ specific and systemic autoimmunity, auto inflammation, primary immunodeficiency and allergy. He has a number of diagnostic and research interests including the determinants of good clinical decision making. He is a clinical senior lecturer with the Christchurch School of Medicine and Health Sciences, University of Otago and advanced trainee supervisor and past examiner for both the Royal College of Pathologists of Australasia (RCPA) and the Royal Australasian College of Physicians (RACP). He is a past NZ president, past board member and past Honorary Treasurer RACP and past president of the New Zealand Rheumatology Association. He holds a graduate diploma from the Australian Institute of Company Directors. He has provided advice to Health Commissioners (and other government agencies) in both New Zealand and Australia. He was a member of the Choosing Wisely working group and is a member of the Ambulatory Therapies Governance Committee of the CDHB.