 Born in West Yorkshire, he served as a fighter pilot in the First World War before resuming medical studies in Edinburgh.After working and teaching in the Royal Infirmary of Edinburgh in the 1920s and 1930s, Illingworth was appointed Regius Professor of Surgery, Glasgow, in 1939.Over the next 25 years, he established the Glasgow School of surgery, with generations of his students influencing surgical research and teaching in Britain and abroad.