Politician. Born on his family estate at Whittingehame, East Lothian, his father died when Balfour was just seven and further tragedy struck when his younger brother, the eminent scientist Francis Balfour, died in 1882 as the result of a climbing accident.
Balfour was educated at Eton and Trinity College, Cambridge. He was elected as Conservative Member of Parliament for Hertford in 1874 and by 1878 was private secretary to his maternal uncle, the 3rd Marquess of Salisbury, who held the appointment of Secretary of State for Foreign Affairs in Disraeli's administration. In 1885, Balfour was elected for a Manchester constituency and his uncle became Prime Minister. Salisbury appointed Balfour to senior positions, including First Lord of the Treasury and Leader of the House of Commons. He became known as a formidable parliamentary debater.
Balfour succeeded his uncle as British Prime Minister, serving between between 1902 and 1906, during which time he sponsored an Education Act (1902), which became known as the 'Balfour Act'. His administration also strengthened the defence of the British Empire, encouraged the sale of land to tenant farmers in Ireland and came to an agreement with the French over the division of North Africa. He tendered his resignation in December 1905, following disagreements over free trade, and lost the General Election the following month, but remained Leader of the Conservative Party until 1911. He returned to government during the First World War, becoming Foreign Secretary under David Lloyd-George. The 'Balfour Declaration' of 1917 promised the Zionists a home in Palestine. Balfour returned to government once again in 1925, under Stanley Baldwin.
Balfour was appointed Chancellor of the University of Edinburgh in 1891. He was also a noted golfer, who did much to publicise the sport in England. He was Captain of the Royal and Ancient Club in 1894.
Balfour died in Surrey and is buried with his family in the grounds of Whittingehame House.