He entered the Inner Temple in 1822 and was called to the bar in February 1827. Cooper practised on the Oxford circuit until 1838, and was then appointed judge at Adelaide, in the colony of South Australia.

In September 1860 was sworn in as a member of the Executive Council of South Australia, which was part of the government in the now self-governing colony.

Cooper retired from the bench in November 1861 and from the Executive Council in August 1862 owing to ill-health, and was given a pension of £1000 a year.

He returned to England in 1862, resided at Bath, Somerset, and improving much in his health lived to be 92 years of age.

His sister Sarah Ann Cooper (c. 1804 – 31 May 1895) married William Bartley (1801–1885), Senior Solicitor to the Lands Titles Office, on 23 September 1852.