Ronald Nicolson O’Reilly was born on 18 January 1921 in Winton, Queensland. Raised in Winton and Barcaldine, he went to Brisbane Boys’ College, and then studied medicine at the University of Queensland, graduating in 1945.

Ron completed his residency at Brisbane General Hospital and established a general practice in suburban Chermside. He soon realised that his vocation was with children, and undertook training in paediatrics at the Royal Children’s Hospital in Melbourne.