Hood joined the diplomatic service in 1935 as Assistant Principal in the India Office, attached to the Political Department. In the years 1936–1939 he served as Assistant Private Secretary to the Secretary of State for India, then the Conservative peer Lawrence Dundas, 2nd Marquess of Zetland. He was promoted to Principal Private Secretary on 26 May 1939, but was then transferred to the Ministry of Information in November of the same year, where he served under three Cabinet Ministers, including Duff Cooper. According to John Colville's diaries, Hood found working under Cooper particularly frustrating, labelling him 'very lazy', and that it was 'impossible' for the Ministry to operate with him at the helm. However, Hood established a fruitful working relationship with Cooper's successor Bracken, stating: 'Only when Brendan Bracken became Minister...did the MoI become really efficient and respected.' Hood was moved to the Foreign Office on 16 September 1942. He was a member of the UK delegations to meetings of the Council of Foreign Ministers in London, Paris, New York and Moscow in 1945–1947, including the Paris Peace Conference in 1946. On 14 January 1947 Hood was appointed as a Foreign Service OfficerGrade 7 in the senior branch of the Foreign Office. At the same time he was made deputy to the then Foreign Secretary, Ernest Bevin, in the drafting of the peace treaty with Austria. In June of the same year he was transferred to Madrid, where he was chargé d'affaires of the embassy. Hood then moved to the Paris embassy on 4 July 1948 and was promoted to Foreign Service Officer Grade 6. On 1 October 1951 Hood was appointed head of the Western Organisation Department and remained there for five years. He was promoted to Grade 4 on 4 September 1956 and made Assistant Under-Secretary at the Foreign Office. In 1956 he was also appointed as the British Permanent Representative to the Council of the Western European Union, and was then transferred to the Washington embassy in 1957, where he was Minister until 1962. In 1963 he was transferred back to London and made Deputy Under-Secretary for Western European affairs at the Foreign Office, remaining in this post until his retirement in 1969.
Later life
After his retirement, Hood remained active in public life. He took up his seat in the House of Lords, and in 1971 became Deputy Speaker and Deputy Chairman of Committeesof the House, serving until his death in 1981. From 1975 until 1978 he was Chairman of the Advisory Council of the Victoria and Albert Museum. Upon his death in 1981 he was succeeded to the viscountcy by his younger brother, Alexander Lambert Hood.
