Born Hans Guhrauer, John Ashley Soames Grenville left Germany for Great Britain in 1939 as part of the Kindertransport. He attended Birkbeck College and the London School of Economics, where he studied under Sir Charles Webster and received a First Class Honours Degree in History in 1951 and a PhD, for which he was awarded the Hutchinson Medal, in 1953. Grenville began his academic career at the University of Nottingham where he was an assistant Lecturer and Reader in History. He was Professor of International History at the University of Leeds from 1966 to 1969, then Professor and Head of the Department of Modern History at the University of Birmingham from 1969 to 1994. He later worked at Hamburg University and London's Leo Baeck Institute.