Sir John Winthrop Hackett Senior KCMG (4 February 1848 – 19 February 1916), generally known as "Winthrop Hackett", was a proprietor and editor of several newspapers in Western Australia, a politician and a University chancellor.
Hackett was born near Bray, County Wicklow, Ireland, the eldest child of the Rev. John Winthrop Hackett, M.A., and his wife, Jane Sophia Monck-Mason, (daughter of Henry Monck-Mason, LL.D.). Educated at Trinity College, Dublin, he graduated BA in 1871 and MA in 1874. He was called to the Irish bar in 1874, but emigrated to Sydney, in 1875 where he was called to the New South Wales bar in the same year.
Hackett took up journalism and contributed to the Sydney Morning Herald, but in 1876 went to Melbourne to become vice-principal and tutor in law, logic and political economy, at Trinity College. He also contributed to The Age and the Melbourne Review. In 1880 he was a candidate for Normanby at an election for the Victorian Legislative Assembly as an advanced liberal, but was badly defeated and lost his deposit.
At a later election Hackett was opposed to John Madden, and this time lost by only a small margin. In 1882 he resigned his positions at Trinity College and went to Western Australia to become a squatter in the Gascoyne district. His first season was a bad one and he decided to give up the land. He joined forces with Charles Harper, the proprietor of The West Australian, and very soon his influence on this paper began to be felt. The Western Mail was established in 1885 and both papers became prosperous. In 1887 Hackett became editor of The West Australian and was a strong advocate of responsible government. Western Australia received its constitution in 1890, and Alexander Forrest selected Hackett as the first man to be asked to join the nominee Western Australian Legislative Council. The population of the colony was still under 50,000 but was beginning to rise, and the discovery of gold accelerated this. The newspapers grew with the population and became very valuable properties. Hackett, as editor, was writing a daily leading article, and was also the business manager.