He was born in London on 19 May 1802, and apprenticed to his father's trade of printing. Under the influence of Richard Watson he became a WM local preacher. The tradition that he was called to the ministry but withdrew on his marriage to the daughter of Samuel Woolmer (e.m. 1797; d.1827) is unsubstantiated. He became a teacher and was headmaster of the WM day school in Great Queen Street, London before sailing for Australia in April 1838. His wife Mary died suddenly in 1842 and a year later he married Hannah Edwards of Stroud, Glos.
The Aboriginal Protection Society was successful in persuading the British Government to set up the Port Philip Protectorate (south of present-day Melbourne) in 1837. Two of the Protectors appointed, Parker and James Dredge, were Methodists. Their duties included championship of aboriginal rights against European aggression and the encouragement of civilization and social improvement among the native inhabitants. In the face of opposition from European settlers the Protectorate declined after 1843 and ceased to function in 1850. Parker's understanding of aboriginal society and culture was extensive, though limited by his Christian stance. For a short period from August 1853 he served as a nominated member of the Victoria Legislative Council and took a stand against the evils of intemperance. From 1857 to 1862 he served as an Inspector for the Denominational Schools Board, making a variety of recommendations for educational improvements. In his closing years he wielded influence both as preacher and as a public figure, but following an unsuccessful bid for re-election to the Legislative Assembly he died on 27 April 1865.