 Illingworth's administrative and leadership roles included his Presidency of the Royal College of Physicians and Surgeons of Glasgow (1962 to 1964) and Dean of Faculties at the University of Glasgow (1978 to 1981).His honours included a knighthood (1961), Honorary Surgeon to the Queen in Scotland (1961 to 1965), and a range of honorary degrees.Honorary fellowships included those conferred by the Royal College of Surgeons of England, the Royal College of Surgeons in Ireland, and the Royal College of Physicians and Surgeons of Canada.