John Lister Colless Lahz was born in Murgon, Queensland, on 29 November 1925, the son of Rudolf Sergius Lahz a surgeon, and Mary Regis, née Barron. He attended Loreto Convent, Coorparoo, Queensland, and St Joseph's College, Melbourne, and later the University of Queensland Medical School in Brisbane. He qualified in 1949 and his early posts were as resident medical officer at Brisbane General Hospital and later in the orthopaedic section of the Children's Hospital at Frankston, Victoria. He then became orthopaedic registrar at Mater Hospital, Brisbane, before coming to England in the later part of 1953. He was appointed senior house surgeon at St Helier Hospital, Carshalton, and passed the FRCS in the following year. He gained further experience in orthopaedic surgery, initially at the Royal National Orthopaedic Hospital and then as registrar at St Thomas's Hospital before returning home in 1957. Within a few months he was appointed orthopaedic surgeon to the Princess Alexandra Hospital in Queensland and also to the Department of Renatriation in the Commonwealth of Australia. He passed the FRACS in 1960 and in 1972 was appointed Chairman of the Queensland State Committee of the Royal Australasian College of Surgeons. He was President of the Australian Orthopaedic Association in 1985. In 1956 he married Jean Blinman Brown of London and there were two daughters of the marriage. He died on 21 September 1987, aged 61.