Geoffrey Alfred Penington was born in Melbourne, into a strict Methodist family. His father, a meticulously methodical man, rose from the position of wharf tally clerk to company secretary. After a state school primary education, Geoffrey attended University High School, as did his sister and one brother. Senior government scholarships enabled the three to attend the University of Melbourne, Frances becoming a lecturer in history and later a social worker, and Raymond a medical missionary. The youngest brother Alan FRACP specialised in the field of thoracic medicine. The eldest brother died of wounds at Gallipoli.

Geoffrey desired excellence in all that he attempted, including university football, tennis and, later, golf and bowls. Obsessive attention to detail and to regulation made him an earnest member of the AAMC from 1924 and later a commander of AIF general hospitals. In the latter role, his attitudes won him respect, friends and critics.

Geoffrey was appointed to the Royal Melbourne Hospital as honorary physician to outpatients in 1928, while in general practice in suburban Melbourne. After a year of treatment for tuberculosis, general practice was relinquished and a consultant practice in medicine was established in Collins Street, in rooms shared with Albert (later Sir Albert) Coates. The administration of anaesthetics for Albert, during the morning operating sessions, helped Geoffrey maintain peace in the operating theatre, as well as providing butter for the family bread.

Geoffrey will be remembered best as an astute clinician and a stimulating undergraduate teacher. At the Royal Melbourne Hospital, following his appointment as physician to inpatients in 1946, he developed a `medical unit', a concept new to the Hospital at the time. On his retirement from the Royal Melbourne Hospital in 1959, he was farewelled by a large gathering of ex-students and housemen, to whom he was affectionately known as `The Boss'.

As a meticulous editor of the Royal Melbourne Hospital Clinical Reports, a conscientious medical staff committee man, a mentor of the clinical biochemistry department, as lecturer in therapeutics at the Royal Melbourne Hospital and as Stewart Lecturer at the University of Melbourne, he displayed a capacity for hard and effective work. The role of dean of the clinical school led to difficulties in disciplining such purposive and formidable colleagues as Sir Alan Newton and Dr Ewen Downie. It was as dean of the clinical school that he was able to assist the first professor of medicine in the University of Melbourne to establish himself and his department at the Royal Melbourne Hospital. He held office in The Royal Australasian College of Physicians as vice-president from 1968 to 1970.

Apart from medicine, Geoffrey had no consuming interests, although his sporting activities gave him great and continuing satisfaction. He was pleased to have played a good eighteen holes six weeks before his death from prostatic carcinoma which, in the three years following its diagnosis, had not prevented him from functioning as president of the Rotary Club of Melbourne and the Wallaby Club, nor from participating as a member of the Masonic Grand Lodge.