For the 1880s, this was in some ways contrary to the Gothic Revival style which was popular at the time and features in numerous contemporary buildings in Preston, including the old Town Hall which stood on the western side of the Harris.

[3] The building's exterior reflects Hibbert's vision of a neo-classicism through “simplicity, symmetry of plan, truthfulness of expression and refinement of detail”.

Interpreting Hibbert's design fell to London sculptor Edwin Roscoe Mullins and features the central figure of the Ancient Athenian general Pericles, surrounded by twelve other men arranged symmetrically to either side.

[5] The fine art collection includes over 800 oil paintings featuring work by Richard Ansdell, George Frederick Watts, Lawrence Alma-Tadema, Stanley Spencer, Lucian Freud, Ivon Hitchens and Graham Sutherland as well as local artists Anthony Devis and Reginald Aspinwall.

The building is also decorated with a number of plaster casts of classical friezes throughout the central atrium and a 19th-century copy of the Baptistery doors from Florence is located on the ground floor.

[12] Following a successful bid for support from the National Lottery Heritage Fund, in October 2020 plans were submitted for a £10.7M renovation and restoration project called #HarrisYourPlace with the aim "to establish the Harris as the UK’s first blended museum, art gallery and library".

The project is said to include "much-needed conservation works" on the roof, stonework and basement to help address the building's "long-standing damp problem".

A new lift and toilet on the ground floor will improve the building's accessibility to disabled visitors, and a new staircase will replace the existing fire exit stairs.