In 1945, Browne became Secretary of the Pilgrim Trust. During his tenure as secretary, the Pilgrim Trust broadened its objects, and began to focus more on cultural heritage. As secretary, Kilmaine called for the establishment of a national organisation to organise fundraising for church repair. Kilmaine then acted as trustee of the Historic Churches Preservation Trust which was founded following the publication of the Church Assembly's report "The Preservation of Our churches". In 1949 he was made chairman of the Oxford Society and served in this capacity until 1973. As chairman he organised an exhibition of items from the collections of the Ashmolean and the Bodleian in Goldsmiths' Hall, London, to coincide with the Coronation of Elizabeth II and the twenty-first anniversary of the Society. In 1956 he was appointed a CBE for his services to the nation. In 1972 he was awarded an honorary doctorate in civil law from the University of Oxford in recognition of his work. In his other roles as public servant he was a Vice-President of the Friends of Lambeth Palace Library, as well as a Trustee of the Dulverton Trust. He also served as the High Steward of Harwich from 1966 to 1976.