Wynyard obtained a commission in the
British Army, without purchase, as an ensign of the
85th Regiment of Foot (Bucks Volunteers), aka The King's Light Infantry Regiment, on 25 February 1819. then, after an absence of some seven months, returned with the 58th Regiment to
Auckland, New Zealand, in July 1847. He was promoted to the rank of colonel in 1854. Somewhere along the line he had a sexual relationship with a Maori woman that produced a male child. When a fire broke out in
Auckland, New Zealand, in 1858, eventually destroying an entire city block, Wynyard was personally on the scene directing the men of the 58th Regiment in firefighting efforts.
Lieutenant-Governor of New Ulster From 26 April 1851 to 7 March 1853, Wynyard was Lieutenant-Governor of
New Ulster, a
province of New Zealand encompassing much of the
North Island. He replaced
George Dean Pitt, who had died in office. During his term of office, he persuaded the local chiefs
Ngāti Tamaterā and Ngāti Raupunga to allow gold mining in the province. The office was abolished when New Zealand was divided into several smaller provinces under the
New Zealand Constitution Act 1852.
Superintendent of Auckland Province Wynyard elected Superintendent of the new
Auckland Province on 12 July 1853, beating
William Brown. He held the office until he resigned on 5 January 1855. Wynyard's election to the office was controversial, as he was in charge of the colonial armed forces at the time, and effectively deputy to the Governor. The Colonial Office, on learning that Wynyard had been elected to the office of superintendent, demanded he resign from the role, which he soon did. He was replaced in the role by his previous electoral opponent William Brown.
Administrator of Government Wynyard served for two periods (3 January 1854 to 6 September 1855 and 3 October 1861 to December 1861) as
Administrator of the Government, in each case between the recall of one
Governor and the arrival of the next. Wynyard opened the
1st New Zealand Parliament on 24 May 1854. On 28 January 1858, Wynyard was appointed to the
New Zealand Legislative Council. He resigned on 3 November of that year, as the 58th Regiment was recalled to England.
Auckland Museum Robert Henry Wynyard (48753649512) (cropped).jpg|Silhouette portrait of Robert Wynyard The Residence of Colonel Robert Henry Wynyard, Emily Place, Official Bay, Auckland (c. 1843).jpg|
The Residence of Colonel Robert Henry Wynyard, Emily Place, Official Bay, Auckland (c. 1843) by
Edward Ashworth Cape Colony He acted for Sir
George Grey as
Governor of Cape Colony twice, from 1859 to 1860 and from 1861 to 1862. ==Later life==