Brian O'Sullivan spent his childhood on a sheep property near Muckadilla in Western Queensland, the youngest in a family of six boys. He spent his early adolescence at boarding school in Brisbane, graduating in medicine from the University of Queensland in 1955. After completing his internship at Brisbane General Hospital, O'Sullivan was appointed Medical Superintendent of the Monto District Hospital. In 1967 he returned to Brisbane and worked as a general practioner at Sherwood until 1995. O'Sullivan retired in 1999.
