William Malcolm Hailey, 1st Baron Hailey (1872-1969), was born in Newport Pagnell, Buckinghamshire, England. He was educated at Merchant Taylors' School, and Corpus Christi College, Oxford (he became an honorary fellow of the College in 1925).

Hailey entered the Indian Civil Service in 1895. He was posted to the Punjab where, in 1901, he became colonisation officer for the Jhelum Canal Colony. In 1907 he was appointed to the post of Secretariat Officer and worked in this capacity in the Punjab (1907) and in the Finance Department of the Government of India (1908).

In 1912, Hailey became the first Chief Commissioner of the new province of Delhi, a post he held until 1918. During this period he was also on deputation to the reforms committee whose advice to the Secretary of State culminated in the Montagu-Chelmsford reforms, the main recommendations of which were embodied in the Government of India Act of 1919.

Between 1919 and 1924, Hailey served as a member of the Executive Council of the Governor-General, working in the Finance and Home Departments. He held governorships in the Punjab (from 1924) and the United Provinces (from 1928), and in 1930 was called to London for the Round Table Conference where he played an important part in the discussions which led to the Government of India Act of 1935. Hailey retired from India in 1934, although he continued to act as an adviser to successive Secretaries of State.

After retiring from India, Hailey became director of an expedition sent to carry out a survey of Africa. This survey covered politics, administration and education, as well as soil erosion, irrigation and the improvement of crops. The results were published in 1938 under the title An African survey: a study of problems arising in Africa south of the Sahara.

At the outbreak of the Second World War, Hailey was asked by the colonial secretary to visit the African colonies and to make recommendations on how to secure their support. One of Hailey's proposals was the appointment of Africans to the Colonial Administrative Service. There was influential opposition to this suggestion and although his advice was accepted for the west coast it failed to win acceptance for the east and central African territories.

Hailey returned from his visit to the African colonies in the summer of 1940 and was immediately asked to go to the Belgian Congo as head of an economic mission. When he returned from the Belgian Congo he was appointed chairman of the Colonial Research Fund which had been founded in 1940 to provide government funding for African studies.

In 1952, when he was 80 years old, Hailey undertook a second survey of Africa. He again travelled throughout the continent and each chapter was entirely rewritten. The second survey was published in 1957.

Hailey was an active chairman of many voluntary bodies and received many academic honours. He was raised to the peerage in 1936.