Dr Sharma completed his paediatric specialty training through the Royal Australasian College of Physicians (RACP) in Melbourne and Perth. Dr Sharma then moved to Toronto, Canada, where he finished his clinic fellowship in paediatric gastroenterology and hepatology at the Hospital for Sick Children, University of Toronto.

He has a special interest in paediatric inflammtory bowel diseases, including Crohn's disease, Ulcerative Colitis, Eosinophillic esophagitis, Coeliac disease, Gastroesophageal reflux disease, nutrition and liver conditions in children.

Dr Sharma is fully accredited for paediatric endoscopy and colonoscopy procedures. He also provides 24 hour pH study for chronic reflux patients and multi disciplinary bowel management service.

Dr Sharma treats both public and private patients at St John of God Murdoch Hospital and St John of God Midland Public Hospital. Ajay has published many articles in high impact journals and is also currently Chair- Paediatric Network of GESA-Gastroenterology Society of Australia (Since Nov 2020).