In 1838 Hay married Mary Chalmers and they travelled to Sydney on the Amelia Thompson, arriving on 1 July and settled at 'Welaregang' station on the Upper Murray.

[1][2] Hay was a strong opponent of tariffs on trade between New South Wales and Victoria and was elected in April 1856 as the member for Murrumbidgee in the first Legislative Assembly.

[1][6] In June 1860, Hay moved that negotiations should be opened up with Victoria for the purpose of establishing a uniformity of customs duties.

[2] John Hay died on 20 January 1892(1892-01-20) (aged 75) in the Sydney suburb of Rose Bay, survived by his wife for ten days.

[1][2][6] Hay was not a party man but he had knowledge and wisdom, and though he originated little he was a good speaker and debater who had no little influence on the legislation of his time.