Born in Greenfield, Yorkshire, John Wilkinson was one of the founders of haematology as a clinical speciality in Britain. Initially trained as a chemist, his undergraduate studies were interrupted by the First World War. Within a year of graduation he was lecturer in medical physics and honorary demonstrator in crystallography at the University of Manchester. In 1924 he was awarded a Ph.D, and took his medical degree in 1928. He received the MD with gold medal in 1931.
In 1928 Wilkinson had been made director of the Department of Clinical investigations and Research at the Manchester Royal Infirmary, and in 1934 became a honorary physician at MRI and a member of its medical board. He remained at the Department until 1947. He was reader in medicine and haematology at the University of Manchester from 1947-1962. He was also honorary haematologist at Christie Hospital and Holt Radium Institute, Manchester. Wilkinson carried out much early research into pernicious anaemia and malignant blood diseases and was a pioneer of the use of nitrogen mustards in treating lymphomas and chronic leukaemia. Wilkinson carried out original research on the relationship between gastric carcinoma and anaemias. He also carried out work on diseases of the endocrine system and allergic diseases. Wilkinson was director and organiser of the Manchester and Salford Blood Transfusion Service from 1938-1946 and a regional officer for the North West Blood Transfusion Service from 1939-1946. Wilkinson was chairman of the haemophilia committee of the Medical Research Council, established in 1953. He wrote many papers, was co-founder of the British Society of Haematology, a president of the European Haematology Society, and a life councillor of the International Haematology Society. He was president of Manchester Medical Society in 1956.
Wilkinson had a large private practice. On working days his Rolls-Royce would be parked outside his consulting wing adjacent to the private wing of the Royal Infirmary so that he had easy access to his hospital department, NHS wards, and private patients. He retired from the NHS in 1962, but patients were still being referred to him in his 90s. Outside medicine his interests were scouting, animals (he was director and vice chairman of Chester Zoo), and old pharmacy jars, which are now housed in a special gallery in the Thackray Medical Museum in Leeds. Wilkinson died on 13 August 1998.