During the eighteenth and nineteenth centuries, low relief portraits in wax became popular in Britain and they were often exhibited at the Royal Academy, the Society of Artists and elsewhere. Waxes were used in a similar way to prints and medals, in order to disseminate the image of the sitter, or, like miniature paintings or silhouettes as portable mementoes.

The finishing on this portrait is astoundingly detailed. Low relief polychrome wax portraits were produced using the same basic principles as monochrome ones: modelling in soft wax, taking a plaster mould and then casting. However when the initial mould was finished it was cut into separate sections and each part cast in the prevailing colour. The pieces were then joined together on their backing using molten wax and the surface finishing completed in a similar way. On the surface additional sheets of sculpted wax and chasing has been used to add further detail.

Sir Herbert Mackworth represented Cardiff in Parliament between 1765 and 1790, when he was forced to retire to allow the heir to the Earl of Bute to take over the seat. He was made a Baronet in 1776.