Geoffrey Gurner Wyllie was born in Adelaide on 16 May 1923 the second son of Kenneth Robert Wyllie and Maude Hoban (née Gurner). He was educated at St Peter's College, Adelaide, before entering the medical faculty of the University of Adelaide and the Royal Adelaide Hospital, qualifying in 1946. His first appointment was that of resident medical officer to the Royal Adelaide Hospital but after a year he joined the Royal Australian Army Medical Corps as a Temporary Major serving in Japan with the British Commonwealth Occupation Force. On demobilisation he served as registrar in the radiotherapy department and later in the department of surgery at Adelaide under Sir Leonard Lindon, Sir Phillip Messant and Alan Britten Jones before coming to England in 1952. He passed the FRCS and pursued a career in paediatric surgery working at the Hospital for Sick Children in Great Ormond Street, initially as house surgeon and later as resident assistant surgeon under Sir Denis Browne, DJ Waterston and Sir David Innes Williams. He returned to Adelaide in 1956 and after a brief period as senior registrar was appointed to the consultant staff in 1957, the same year as he passed his FRACS. He continued to practice general surgery with a special interest in paediatrics and was elected a member of the South Australia State Committee of the Royal Australasian College of Surgeons from 1966 to 1972 and as Chairman of that Committee from 1968 to 1970. He also served as Chairman of the medical staff committee of Adelaide Children's Hospital from 1966 to 1978 and as a member of same period. He was a Council member of the Australasian College of Paediatrics and Vice-President in 1980. His outside interests were golf, tennis, woodwork and plant propagation. He married in 1966 Dr Patricia Verco Warhurst in the year of her graduation and they had two daughters and one son. He died on 17 July 1989 shortly after retiring from practice.