Ronald Hoy was the only son of Charles Andrew Hoy and Jessie Colquhoun (nee Budge.) He had one sister, Viv. Charles was an architect who became Director of Works in New South Wales and from 1939 was Commonwealth Director-General of Works in Canberra and a member of John Curtin's War Cabinet.

During a happy childhood in Manly, Ron became an accomplished pianist and a strong swimmer. He was a member of Manly Surf Lifesaving Club. Ron attended Sydney Boys High and then Sydney University, commuting by bus, ferry and train for more than 10 years, during which he watched the Harbour Bridge grow, and developed his life-long love for the harbour and for Sydney.

The Great Depression prompted Ron, as a young medical student, to enrol in the Sydney University Regiment. However he felt he had no real talent for military matters and was relieved to discard the uncomfortable uniform in 1938 when preparing for his final medical exams. During his first-year residency, at Brisbane General Hospital, two momentous developments occurred for him: war broke out in Europe, and he met Eleanor Mary Wilson, known as "Billie", a nursing sister.

Back in uniform as a Captain in the Australian Army Medical Corps, Ron trained with the 2/15 Battalion in Queensland and Darwin before its transfer to Palestine in early 1941. His command consisted of two ambulances, a handful of medics and stretcher-bearers, two baskets of basic equipment, and no drugs more effective than aspirin. Ron's driver had salvaged an abandoned Italian four-wheel-drive vehicle that proved invaluable in the battalion's advance with the 19th Division across North Africa. When they were more than 1000 kilometres west of Cairo, near El Agheila, the Australians met with resistance from tanks and planes and were ordered to withdraw 600 kilometres to Tobruk. This retreat was a chaotic and desperate one, accompanied by extreme heat, dreadful dust storms, exhaustion and lack of communication.

Two weeks later Ron's group, with overloaded ambulances, arrived at Tobruk just hours before a tank attack which was repelled with the assistance of British artillery. This was the first effective repulse of German forces in World War II and pivotal in engendering the fierce resistance that became the hallmark of the legendary "Rats of Tobruk".

Repatriated in September 1941, Ron was sent to Charters Towers as Executive Officer of the Army General Hospital. He described this time as "the darkest years of the war". German and Japanese successes were mounting, and casualties from Papua New Guinea and the Pacific were flooding into his poorly equipped hospital. Still, the young Major found time to marry Billie and to pass his MRACP exams. In late 1943 he was posted to the Australian General Hospital at Kenmore, in Goulburn and he, Billie and their children settled in the town, where they lived for the next 12 years.

Ron was a founding member of the Goulburn Medical Clinic, one of the first group practices in NSW. He practised as physician, anaesthetist and radiologist, and encouraged some others, most notably the pathologist, Alan Hazleton, to join them. Later Ron's fellow practitioners encouraged him to qualify in radiology, which he did at the Alfred Hospital in Melbourne, living there for some months while his family remained in Goulburn. In 1955 the family moved to Canberra where, with partners Dr Gwen Pinner and Dr Bruce Collings, he founded ACT X-Ray, which serviced all major hospitals from Goulburn to Cooma and Yass to Queanbeyan.

At about this time Percy Ford, the medical clinic's accountant, invited Ron to join a small group of Goulburn businessmen in financing the building of a motel in Gundagai, in a venture that subsequently became Motels of Australia, and later Travelodge Australia and Travelodge International. Later Ron proudly recalled attending, along with fellow director and builder, Tom O'Connor, the opening of the Tidbinbilla Tracking Station, which their company had built.

In 1965 Ron and Billie moved to Sydney where he pursued two parallel careers: director of staff training with Travelodge and, applying similar principles to radiology training, an academic appointment at the University of New South Wales. This latter work led to associate and professorial positions in Malaysia, the United States (Yale and Pittsburgh) and Vietnam.

Around the time of Billie's death in 1976 Ron returned to Australia, working at Melbourne's Alfred Hospital, the Brisbane General Hospital and Royal North Shore Hospital in Sydney, where he met Geraldine Borthwick. They married in 1981 and returned to Pittsburgh, where Ron's innovative training program resulted in an 'invasion' of talented Australian radiologists. Ron was revered by his students and to this day the "Ronald Hoy Excellence in Teaching Award" is awarded annually by the radiology residents at Pittsburgh to the faculty member who best exemplifies the dedication and excellence in teaching that he modelled.

Ron and Geraldine returned to a busy retirement in Mosman, overlooking Ron's beloved Sydney Harbour and Manly. He enjoyed his regular contact with returned service men and women at the Mosman branch of the RSL, and in 2005 was honoured to be among the NSW veteran doctors from World War II awarded Certificates of Appreciation by the AMA at a reunion lunch. Geraldine died in 2004.

Ron was a cultured man of irrefutable integrity, with a formidable intellect and memory, compassionate and quick-humoured. He was a gifted teacher, a generous colleague and a loyal friend. Always modest, kind and gracious, even fading eyesight in his latter years failed to constrain his enjoyment of his growing family and his fabled lunches with old colleagues and friends old and new.

Ron is survived by his three children, Judith, Wendy and Charles; daughter-in-law Lindy and son-in-law Philip; eight grandchildren and seven great grandchildren.