Despite failing health, he continued to attend parliament, and maintained his support for tenant rights and for "mixed" (Catholic, Protestant) education.
William was born to Mr. Hugh Kirk and the former Miss Eliza Miller in Larne, in 1795, and followed his father into business: the manufacture of linen.
In 1837 he bought the Annvale finishing mill in 1837 in Keady, south Armagh, and expanded it to include weaving as well as bleaching and dyeing.
Kirk was very interested in the technical side of the industry, and by 1848 had designed and installed the first water turbine in one of his own beetling mills near Keady.
His business holdings would eventually expand to include an imposing warehouse in the centre of Belfast, and branches or agencies in London, Manchester, New York and Paris.
[4][3] The workers' houses that still shape the profile of Darkley village were constructed with the assistance of a government grant secured by Kirk.
[2] In 1865 he unsuccessfully challenged his conservative opponents in Armagh while his son William Millar Kirk contested, but failed to carry, the Newry seat.
In his nomination speech Kirk had focussed on his support for the disestablishment of the [Anglican] Church of Ireland and reasserted his commitment to religious equality.
[7] His son Thomas Sinclair Kirk (1869–1940) was a prominent Belfast surgeon, President of the Ulster Medical Society 1908–09,[8] and during the First World War a noted pioneer in the use of urea for sterilising wounds.