Ewen Downie was the son of Thomas Taylor Downie and Katherine Maude Smith. His father, a graduate of the University of Glasgow, migrated to Australia in 1888 and became well known as an obstetrician. Ewen graduated from the University of Melbourne and spent two years as a resident and registrar at the Alfred Hospital, the institution with which he was to remain associated for the remainder of his professional life. He made the conventional pilgrimage to London where he worked with Francis [later Sir Francis] Fraser at St Bartholomew's Hospital. While in London he became a member of the Royal College of Physicians (RCP).

On return to Melbourne he started practice as a consultant physician with a particular interest in diabetes and during the course of the next few years established a special clinic for the care of diabetics. He also spent three years at the Baker Institute for Medical Research working on aspects of carbohydrate metabolism. He was awarded the Armytage Prize for medical research in 1931. Diabetes was to remain one of Downie's abiding interests for the rest of his life. He continued to promote the interests of diabetics and diabetes and by the mid-1950s he had attracted a small group of researchers for whom he established an environment in which basic and clinical research was possible. This special medical unit was known as the diabetic and metabolic unit and in 1968 was named as the Ewen Downie Diabetic and Metabolic Unit and still bears his name today.

His contributions to the fields of metabolism, nutrition and diabetes had earned him a reputation outside Australia. In 1955 he was invited to give a Banting Lecture at the University of Toronto and in 1957 the Lilly Lecture to the American College of Physicians. In 1950 he delivered the Annie B Cunning Lecture for the College on 'Food and mankind'. His continued interest in diabetes and metabolism resulted in the recognition of endocrinology as a sectional specialty in internal medicine and to the formation of the Endocrine Society of Australia of which he was the first president 1958-60. He continued to practise almost until he died always championing the cause of patients with diabetes.

He was also interested in medical education and at the same time as he was appointed as a physician to outpatients at the Alfred Hospital he became sub-dean of the clinical school (1932). He continued his interest in student and educational affairs for the next twenty-five years. After his return from the war he became dean of the clinical school and was for two years (1947-48) the Stewart Lecturer in Medicine at the University of Melbourne which at that time had no clinical professors; the appointment to the Stewart Lectureship was a de facto professorial appointment. His association with the Alfred Hospital was over a forty year period, from the time he entered as an undergraduate medical student in 1922 until he retired in 1962. He was a member of the board of management for the last ten years of this association and vice-president for the last two years.

In 1932 he married Muriel Mary daughter of John Cumming, a member of a well known pastoralist family. They had one son (Ewen jnr) and one daughter (Margaret). Downie served in the Australian army during the Seconf World War. He held a number of senior post and was ADGMS in Washingto DC in 1944. He ended his army career as a colonal.

Downie continued to practise almost until his death despite a substantial physical disability (laryngectomy). Notwithstanding his problem of speech, he participated in public meetings and never lost interest in the affairs of the diabetic. His fortitude during these latter years was a source of admiration of both friends and critics. Downie did have his critics. He did not tolerate fools and could be quite acerbic with colleagues and others who had not gained his respect. He believed in the established order of events and was intolerant of those who created disorder. He was however intensely loyal to those who served him well and spared no effort to help younger people in their careers.