Bony taught French as an Assistant Master at Eton College from 1937 to 1939. On the outbreak of the Second World War he returned to France and served in the French Army; he was captured, and spent from 1940 to 1943 in prisoner-of-war camps, where he continued his interest in medieval architecture, writing articles, compiling notes, making detailed drawings, and giving educational talks to his fellow-prisoners. He left the French Army as a first lieutenant in 1944. Returning to the UK after the war, he taught briefly at Eton again (1945 to 1946), then became a Reader at the French Institute in London (1946-1961). In parallel with this he was a Visiting Lecturer (1948-1958) and external examiner (1950-1958) at the Courtauld Institute of Art, University of London. With George Zarnecki of the Courtauld he began a project in around 1960 to compile an exhaustive inventory of Romanesque sculpture in the British Isles, which Zarnecki eventually completed after Bony's death. No doubt through Zarnecki's influence, Bony contributed photographs to the Courtauld Institute's Conway Library, an extensive archive of architectural images currently undergoing a digitisation process. Bony has had a great influence on medieval scholarship within The Courtauld Institute, well beyond his time spent there, and still evident in the work of recent and current Courtauld scholars.