Soon after his birth in Adelaide, John Fitzwater's family moved to Melbourne, where his father was a business executive concerned in the sale of motor vheicles and farm machinery. After completing his secondary education at Xavier College he attended Melbourne University Medical School, graduating in 1940. Desirous of a change of scene he gained an appointment as a junior resident medical officer at the Mater Misericordiae in Brisbane. During his nine months on the staff there he met his future wife, Nancy Warburton.

In 1941 John fitzwater joined the army, first the CMF, transferring soon afterwards to the AIF. He served in the 2/16 Field Ambulance and the 2/6 Australian General Hospital, taking part in the construction of the Bulldog-Wau Road and landings at Tarakan and Labuan. Possibly the most demanding part of his service from his point of view was the necessity to perform an appendicectomy in an ill-equipped theatre on a Victory ship on the voyage back to Australia. The patient recovered. He took some pride in being one of the most senior captains in the Australian Medical Corp. After demobilisation in 1946 he spent a short period in the army reserve.

Realising that his experience up to then had not equipped him for future medical practice, he began work as an assistant to Dr HS Waters in general practice at Enoggera, Brisbane, later buying a practice in Ascot from Dr Duncan Fowles. Though he soon developed a large following, he decided that his interests lay in the field of internal medicine. In 1951 he returned to the public hospital sphere, becoming a medical registrar at the Brisbane General Hospital, where he was associated with the then professor of medicine, Dr (later Sir) Alexander Murphy. He passed the examination for Membership of the College in 1952 and was elected to the Fellowship in 1961.

In 1953 he began practice as a consultant physician at Ballow Chambers, Wickham Terrace, being appointed in the same year to the position of assistant physician in outpatients at the Hospital. In 1955 he became junior physician and in 1959 transferred to the Princess Alexandra Hospital (which had opened in 1956) with the appointment of senior physician, remaining there until his retirement from public hospiatl service in 1977. He was also a visiting chest physician at thew South Brisbane Auxiliary Hospital (the predecessor of the Princess Alexandra Hospital) from 1953 to 1958 and a visiting physician at the Chermside Hospital (now Prince Charles Hospital) from 1959. On retirement from the State Hospital Service at the age of sixty he was appointed honorary consultant physician to the Repatriation Department. He was taken ill in 1984 and died in 1985. Between periods of treatment he continued to see patients, even struggling into his rooms the day before his death in order not to disappoint two patients who had travelled from another town to see him.

That John Fitzwater was held in high regard by his peers is confirmed by an impressive list of appointments in the medical world. He served the College as a member of the Board of Censors from 1965 to 1974, his arrangements for the Membership examination in 1968 in Brisbane drawing praise from the chief censor. He was a member of the College council from 1964 to 1976; in 1968 he was a visiting lecturer in the University of Singapore, assisting candidates for the membership examination. In 1966 he was awarded the Pharmaceutical Manufacturer's Travelling Fellowship. A member of the British Medical Association and subsequently the Australian Medical Association since 1944, he became president elect of the Queensland branch in 1967, president in 1968-69 and was ex-officio a vice-president of the third Australian Medical Congress in 1968. From 1970 to 1976 he was a member of the Commonwealth Specialist Recognition committee in Queensland, was a director of the Australian Medical Agency (Queensland) and was a president of the Thoracic Society of Queensland. In 1977 he was awarded the distinction of election to the Fellowship of the Australian Medical Association and in 1984 the medal of the College of Physicians, the first Queenslander to receive this honour. He was a member of the Medical Board of Queensland from 1965 until his death and was also for three years a member of the Psychology Board.

John Fitzwater was a good natured, tolerant, thoroughly decent man of total honesty and reliability, a sound clinician and enthusiastic bedside teacher. He and Nan married in 1942. It was a major misfortune to them both that they did not have children, but this was balanced by their devotion to each other, with a shared enjoyment of golf and gardening.