Born and raised in Perth, Mr. Duncan-Smith attended the University of Western Australia and completed his Bachelor degree in medicine and surgery in 1987. His studies continued in the plastic and reconstructive specialist area, finishing in the latter half of 1996. He obtained his Fellow of the Royal Australasian College of Surgeons (FRACS) in 1997. Specialist post-graduate studies in plastic surgery were undertaken in the USA. He opened his practice in 2000.
Mr. Duncan-Smith is a Fellow of the Royal Australasian College of Surgeons (FRACS), Royal College of Surgeons and a member of the Australian Society of Plastic Surgeons. He is Head of Department, Plastic Surgery, at Royal Perth Hospital (2008 - 2014) and a consultant plastic and reconstructive surgeon at The Western Australia State Adult Burns Unit.
He was one of the 2 consultant burn surgeons who work on the acute burns of the Bali Bombing Disaster and more recently also was the clinical lead for the Ashmore Reef Burns Disaster.
A past president of the West Australian Society of Plastic Surgeons (WASPS), Mr. Duncan-Smith lectures and trains future plastic and reconstructive surgeons.