 Between 1853 and 1861 Oliphant was secretary to Lord Elgin during the negotiation of the Canada Reciprocity Treaty in Washington, and companion to the Duke of Newcastle on a visit to the Circassian coast during the Crimean War.In 1861, Oliphant was appointed First Secretary of the British Legation in Japan under Minister Plenipotentiary (later Sir) Rutherford Alcock.He arrived in Edo at the end of June, but on the evening of 5 July, a night-time attack was made on the legation by xenophobic ronin.