John trained in paediatrics and nephrology in Sydney and London, then worked as an academic paediatric nephrologist at the Royal Alexandra Hospital for Children in Sydney, where he founded the Centre for Kidney Research. For four years he was Medical Director of the Australian Kidney Foundation. Then he worked in therapeutic risk management and pharmacovigilance for a decade for Johnson and Johnson in Europe and Asia. He returned to academia in 2014 as a Professorial Fellow at the George Institute for Global Health in Sydney, where he is also Director of China-Australia Partnerships. His current research concerns dialysis access and outcomes, particularly in resource constrained environments.