After leaving Oxford, he joined the
Territorial Army on 8 April 1927, as a second lieutenant in the 6th/7th Battalion of the
Black Watch. Wedderburn was elected
Unionist Member of Parliament (MP) for
West Renfrewshire from 1931 until 1945. He was appointed to be PPS to the President of Eden's board for two years before moving to the Ministry of Agriculture. In 1935, he was PPS to the Secretary of State for Scotland before being promoted as
Under-Secretary of State for Scotland until the outbreak of the war. He served in the
Second World War as an officer with the 7th Battalion, The Black Watch from 1939 to 1941, leaving with the rank of captain. Scrymgeour-Wedderburn was wounded so returned to London politics. He was briefly Joint Under-Secretary of State for Scotland from 1941 to 1942. He was chosen as a member of the parliamentary delegation to China just as Japanese soldiers stormed
Singapore. The delegates promised to offer the Chinese military support in a broader alliance to fight the occupation of
Manchuria. On 31 July 1952, the Scrymgeour family's claim to title of Dudhope and Scrymgeour in the Scottish peerage was accepted by the Lords Committee for Privileges; and again on 18 May 1953 his claim to the earldom of Dundee and Lord Innerkeithing was affirmed. On 30 July 1954, he was created
Baron Glassary, of Glassary in the County of Argyll, in the
Peerage of the United Kingdom, giving him an automatic seat in the House of Lords (not guaranteed by his Scottish peerages). Macmillan chose Dundee
minister without portfolio from 1958 to 1961 owing to a wealth of experiences at home and abroad. Dundee was successfully promoted to number two in the Foreign Office as
Minister of State for Foreign Affairs from 1961 to 1964. Simultaneously he was Assistant Deputy Leader of the
House of Lords from 1960 to 1962 and Deputy Leader of the House of Lords from 1962 to 1964. In 1959, he was appointed a
Privy Counsellor. Lord Dundee was also the Hereditary
Royal Standard-Bearer for Scotland, a right established by his father before the
Court of Claims in 1902. He was decorated with the award of
Order of the Brilliant Star of China (with Special Cravat). He was awarded an honorary LLD by
St Andrews University in 1954. ==Family==