Dr Brereton graduated from Sydney University in 1983. Initially trained in General surgery and then became a Cardiothoracic Surgeon in 1997. He has been a consultant at Royal North Shore and North Shore Private Hospitals since 1997. 

His interests cover all areas of cardio-thoracic surgery and include:

• Coronary Artery Surgery in particular off pump coronary surgery with minimisation of the risk of stroke in high risk patients
• Valvular heart surgery, with particular emphasis on Aortic surgery
• Pacemakers & Defibrillators
• Thoracic surgery

Dr Brereton is currently Department Head at Royal North Shore Public Hospital.