Alexander Macleay MLC FLS FRS was a Scottish-Australian leading member of the Linnean Society, a fellow of the Royal Society and member of the New South Wales Legislative Council.

The Chief Secretary of New South Wales, known from 1821 to 1959 as the Colonial Secretary, was a key political office in state administration in New South Wales, and from 1901, a state in the Commonwealth of Australia. During much of the 19th century, the Colonial Secretary was the pre-eminent figure in public life. The role of the Chief Secretary changed significantly from the time of its creation in 1821 to its final use in 1995, with various responsibilities changing hands. Nominally subordinate to the Governor of New South Wales from the early 19th century until the beginning of full self-government in 1856, he was effectively a government record-keeper and the officer with responsibility for the general administration of the colony. However, for most of its history the Chief Secretary was in charge of all matters relating to correspondence with government departments, naturalisation, the Great Seal, state security, censorship and classification laws, the arts, Public Health, Aboriginal welfare, Lord Howe Island, and environmental protection and fisheries.