He fitted into colonial society and politics in the pre-responsible government era, but his style was not suited to the democratic politics that began to develop in 1856. In order to improve his poor health, he joined the British East India Company and travelled to India, China and the Cape of Good Hope. He came to Sydney in 1838 as private secretary to Sir George Gipps.
In May of that year he was elected chairman of committees and was again and again re-elected to this position until the coming in of responsible government in 1856.
Parker was elected as member for Parramatta in the first Legislative Assembly and was a candidate for the speakership in May but was defeated by one vote, Daniel Cooper being elected. In September 1856 John Hay carried a vote of no-confidence in the Cowper ministry.
He recommended to Governor William Denison that Parker would be the most likely man to conciliate parties, and that he should be asked to form a coalition government. Premier
Parker offered seats in the cabinet to Cowper and Stuart Donaldson, the preceding premiers, but Cowper declined.
In March 1857 Parker passed an act re-establishing the Sydney municipal council, and other useful legislation was also passed.
lieutenant had been intended to bring in a land bill but the government was defeated on its electoral bill, and Parker resigned on 4 September 1857. In 1858 he returned to England. He does not appear to have ever revisited Australia, and died at Richmond.
In 1846 he was nominated by the governor as a member of the Legislative Council.