Leslie Dunlop's father, a Belfast medical graduate of distinction, migrated to Australia and subsequently moved to Queensland to seek a cure for tuberculosis. Leslie Dunlop was educated at the Ipswich Grammar School and The King's School. He entered the University of Sydney, graduating in 1909. He worked at Sydney Hospital as resident medical officer, from 1910 to 1911 and was subsequently appointed resident skiagraphist, which presumably would now be called radiologist. He remained at Sydney Hospital and was medical superintendent at the outbreak of the First World War.

His war service was distinguished. He enlisted in the First AIF, was attached to 1 Australian Division and was present at the Gallipoli landing. By June and July 1915 the casualties far exceeded the anticipated number and the urgency of the situation resulted in the appointment of Major Dunlop as Divisional Sanitary Officer. The Official History of Australia in the War 1914-18 makes special mention of the keenness and good work of this officer. Dunlop suffered a severe shrapnel head injury, was evacuated to Egypt and later underwent neurosurgery in England. He returned to Australia in 1916, was awarded the VD and resumed his position at Sydney Hospital. He was appointed honorary physician at that institution in 1920 and also held a similar position at the Mater Misericordiae Hospital, Sydney. In 1938 he became a foundation Fellow of The Royal Australasian College of Physicians.

Leslie Dunlop is remembered by his many students as a dedicated, meticulous and elegant teacher. I recall his final year lecture on Hodgkin's disease, containing valuable information, an amalgam of great personal experience and the distilled wisdom of important textbooks of the day. The delivery of his talk moved logically from definition, aetiology, classification, pathology, clinical symptoms and signs, diagnosis and prognosis to treatment which in 1945 consisted of little more than supportive measures.

He retired from the active staff of Sydney Hospital in 1947. During his remaining sixteen years his visits to the Hospital, which he had served a life-time with devotion and distinction, became rare and one can only hope that he was able to devote more time to gardening, his other hobby.