As Dean, Simon was largely responsible for the reconstruction of the war-damaged nave of the cathedral, commissioning Epstein's Majestas or statue of Christ in Majesty.
Translated to Llandaff in 1957, he represented a moderate form of Anglo-Catholicism, notably on one occasion refusing to join in an ovation for a priest who had done a great deal to foster devotion in the Church in Wales to the Virgin Mary.
Key issues which engaged his attention included apartheid (there was a notable altercation with the Glamorgan captain Wilf Wooller over a visiting South African cricket team) and nuclear disarmament.
Simon's remarks concerning the way bishops were elected in the Church in Wales earned him criticism from Carl Witton-Davies and a satire in the Western Mail in 1961 by the writer and broadcaster Aneurin Talfan Davies.
[4] At an earlier date Simon had criticised the ceremonial attached to the Gorsedd of Bards, remarking that the robes of the Archdruid seemed to be approximating those worn by the Archbishop.
Simon accepted several public positions, for periods holding the post of President of the Ecclesiological Society and that of the Cambrian Archaeological Association.