Bankes was the only surviving son of Henry Bankes and the great-grandson of Sir John Bankes, chief justice of the common pleas in the time of Charles I. He was educated at Westminster School and Trinity College, Cambridge, where he graduated B.A. in 1778, and M.A. in 1781. In 1776 he inherited his father's estate at Kingston Lacy.
After leaving Cambridge he sat for the close borough of Corfe Castle from 1780 to 1826; in the latter year he was elected for the county of Dorset, and re-elected in the general election in the same year, but was rejected after a severe contest in 1830. In politics he was a conservative; he gave a general support to Prime Minister Pitt, but preserved his independence. He took an active but not a leading part in nearly every debate of his time, and closely attended to all parliamentary duties.
The 1784 Enclosure Act allowed Henry to create the current Kingston Lacy estate and parkland footprint. He demolished the hamlet of Kingston which was situated adjacent to the 16th-century Keeper's Lodge, diverted the Blandford road (now the B3082) and converted former agricultural land to parkland. He undertook further minor alterations in the 1820s.
He was a trustee of the British Museum, and acted as its organ in parliament. In 1784 he married Frances, daughter of William Woodley, Governor of the Leeward Islands, and left a large family. His second son was William John Bankes, and his third George Bankes. His daughter married Edward Boscawen, 1st Earl of Falmouth. Bankes died at Tregothnan, Cornwall, 17 December 1834, and was buried at Wimborne Minster. William John Bankes succeeded him and took possession of Kingston Lacy.
- "Bankes, Henry (BNKS773H)". A Cambridge Alumni Database. University of Cambridge.
- "Review of A Civil and Constitutional History of Rome, from the Foundation to the Age of Augustus by Henry Bankes". The Quarterly Review. 27: 273–308. July 1822.
|Parliament of Great Britain|
| Member of Parliament for Corfe Castle
With: John Bond 1780–1801
Nathaniel Bond 1801–1807
Peter William Baker 1807–1816
George Bankes 1816–1823
John Bond 1823–1826