After graduating with an MBBS from the University of Queensland Dr Sillar spent most of his early years at the Princess Alexandra Hospital, but he also spent time as the Acting Medical Superintendent at the Biggenden and Surat Hospitals.

Having decided to pursue a career in surgery, he spent time as a Surgical Registrar at the Cairns and the Southport Hospitals. His Urology training was completed in Brisbane, having rotated through the Princess Alexandra, Royal Brisbane, Mater and Greenslopes Hospitals, including an initial six months in 1991 at the Hepato-Biliary Unit at the Princess Alexandra Hospital, at which time he was exposed to laparoscopic surgery. He continued on this interest in laparoscopy during his urology training, and more recently into robotic surgery. He obtained his Fellowship to the Royal Australasian College of Surgeons in Urology in 1994. During his last year of training, he received the Keith Kirkland Prize, the annual research award for Australasian Urology Trainees.

After this Dr Sillar was a locum for 12 months throughout Queensland and Northern NSW, while deciding where he would settle down with his wife, Fiona, whom he had met at the Royal Brisbane Hospital, then eventually ending up in Lismore.

After 10 years, he moved his practice to the Southern Gold Coast, based at John Flynn Private Hospital. He continues to provide a public urology service through the Tweed and Murwillumbah Hospitals. At present, Dr Sillar is the supervisor of training, with an accredited advanced trainee in urology at Tweed Heads Hospital and lectures medical students at Bond University.

Dr Sillar was a former Chairman of the Northern Section (Queensland) of the Urological Society of Australia and New Zealand, and presently is the Head of the Urology Department at The Tweed Heads Hospital.

Outside of work Dr Sillar enjoys getting outdoors to surf, kite-surf and mountain-bike as much as possible.