Son of a West India merchant who was compensated for 400 slaves when the British government
emancipated them during the
1830s, Parker was educated at Eton and University College, Oxford. After some years as a public examiner, Parker served as private secretary to Secretary
of State for the Colonies
Edward Cardwell during his tenure from
1864 to 1866. When the Liberal Party returned to power in
1868, Parker served as
Cardwell's private secretary again during the latter's tenure as secretary of state for war.
He played a considerable role in
Cardwell's army reforms. In
1899, Parker published in three volumes
Life of Sir Robert Peel from his private papers.
Made a privy councillor in
1907, Parker was one of the signatories of the Proclamation of King George V shortly before
he died in
1910.