Born in New South Wales into an upper middle class military family, he was sent home to England to learn about farming.

He stocked the land, put a manager in charge and made another trip to England with his wife and their, at that time, small family.

He moved to New Zealand permanently in 1857 and lived on his large farm, Raukapuka, which stretched from the sea to the foothills, and of which the homestead was located in present-day Geraldine.

He sold his South Canterbury interests and moved to the Waikato, where he bought large land holdings in Hamilton and Thames.

He resigned due to ill health and later tried to re-establish his parliamentary career in a South Canterbury electorate, but was beaten by William Rolleston.

[1] His father was William Cox, an English soldier, known as an explorer, road builder and pioneer in the early period of British settlement in Australia.

[4][7] He met John Cracroft Wilson, who was in search of a healthier climate, and encouraged him to also settle in Canterbury.

[7] The settlements of Geraldine, Winchester, Pleasant Valley, and Woodbury are located on land originally owned by Cox.

[13] Raukapuka Recreation Reserve in Geraldine, partly under the management by the Department of Conservation, commemorates the early ownership.

[4] Cox engaged architect Isaac R. Vialou to design a house on the shore of Lake Rotoroa in Hamilton.

The capital expenditure for draining the land was large, and Cox lost a lot of money through this venture.

[4] Cox was first elected to the Canterbury Provincial Council in May 1862 for the Geraldine electorate and served until October 1864,[18] when he resigned due to increasing parliamentary duties.

[19] When he represented Timaru, there was much dissatisfaction in South Canterbury about the area not getting its share from the provincial government that it was due.

Instead, he had legislation passed in parliament that enabled the establishment of the Timaru and Gladstone Board of Works, which took over some of the functions of the provincial council, and had its assured income.

Her mother moved with them to subsequent homes and died in November 1898 when the family lived in St Albans.

[23][26] The twins had a double wedding at Riverslea farm in South Canterbury on 30 September 1879, three days after their 20th birthday: Kate married Frederick Alexander Whitaker, the eldest son of New Zealand's 5th Premier, Frederick Whitaker (her husband had earlier that month been first elected to Parliament), and Marian married Francis H. Barker, the fourth son of the late Dr Alfred Charles Barker.