 Lewenhaupt was in late 1895 appointed Swedish Envoy and Minister in London, where he served until October 1902.He took part in the ceremonial surrounding the death in early 1901 of Queen Victoria and the accession and coronation of her successor King Edward VII.In 1874 he married Chief Court Mistress Edla Lovisa Carolina "Augusta" Wirsén (1851–1939), the daughter of major, count Carl Emil Wirsén and baroness Ebba Lovisa (née De Geer af Leufsta).