Born on 23 May 1858, the second child and eldest son of Charles Robert Larkin, surgeon, and Hannah Pugh, his wife. He was educated at a private school at Sheerness and at the Liverpool Medical School. Larkin qualified as LSA in 1884 and MRCS in 1885. He returned to Liverpool as demonstrator in physiology and, later, in pathology at the medical school. In 1889 he was appointed assistant surgeon to the Liverpool Stanley Hospital and was elected surgeon in 1890, retiring as consulting surgeon in 1918. He practised at 77 Bedford Street. Larkin was a pioneer of thyroid surgery, and excelled as a teacher, being lecturer in clinical surgery at Liverpool University for many years till 1921. He took a keen interest in the work of the British Medical Association, sat on the Representative Body, and on the Council in 1907-08 and 1915-16. He was vice-president of the section of surgery at the Liverpool meeting in 1912, and chairman of the organization committee of the Association from 1910 to 1915. Outside his professional interests Larkin had a sound knowledge of local history and church architecture, and was the chief authority on the topography of old Liverpool. He was elected a Fellow of the Society of Antiquaries of London on 11 January 1934 and was a vice-president of the Historic Society of Lancashire and Cheshire. He was a good Latinist and French scholar and taught himself palaeography in order to study mediaeval charters. Larkin died on 25 November 1940, aged 82, survived by his wife, Georgina Kathleen Barber, whom he had married on 9 September 1935. There were no children.