[2] Westmacott devoted all his energies to the study of classical sculpture, and throughout his life his real sympathies were with pagan rather than with Christian art.

[9] Among Westmacott's works include: the reliefs for the north side of Marble Arch; the Greek revival pedimental sculptures of figures representing The Progress of Civilisation on the British Museum;[10][11] the Achilles of the Wellington Monument, London; and the Waterloo Vase, now in Buckingham Palace Gardens.

Following the French defeat in the Napoleonic Wars, the vase was presented unfinished to George IV in 1815 by Ferdinand III, Grand Duke of Tuscany.

[2] His Achilles in Hyde Park, a bronze copy of an antique sculpture from Monte Cavallo in Rome, is a tribute to the Duke of Wellington, paid for by £10,000 raised by female subscribers.

[2] Westmacott also sculpted the memorials to William Pitt the Younger, Spencer Perceval, Charles James Fox and Joseph Addison in Westminster Abbey; the statue of Fox in Bloomsbury Square; and those to Sir Ralph Abercromby, Lord Collingwood and Generals Edward Pakenham and Samuel Gibbs in St Paul's Cathedral.

[18] The idea to create a memorial to a British military hero by showing his death in action was a bold departure from the more common use of allegorical figures and personifications of virtue.

[18] The memorial, a free-standing marble group on an oval base, showed Abercromby falling dead from his charging horse into the arms of soldier and established Westmacott's reputation for originality.

[3] Their son, also called Richard Westmacott, followed closely in his footsteps also becoming a notable sculptor, a Royal Academician and professor of sculpture at the academy.