Between 1955 and 1964, Rhodes James worked in the Clerk's Department (the internal civil service) of the House of Commons, first as a Clerk and then, from 1961, as a Senior Clerk.
In 1968, he became Director of the Institute for the Study of International Organisation at the University of Sussex, before moving to work as Principal Officer in the Executive Office of the then Secretary General of the United Nations, Kurt Waldheim, in 1973.