Cardigan's first municipal building was a modest market hall, commissioned by a local publican called William Phillips and erected in Market Lane in 1823. It served the town through the boom decades of the herring fishery and the shipbuilding industry, when Cardigan was the most important port in South Wales. By the mid-nineteenth century — with the port already declining but civic ambitions still expanding — the market hall was felt to be inadequate to the dignity of the borough. The town council acquired a larger site in Pendre, currently occupied by the local grammar school and a house and coach-house owned by Abraham Morgan. The mayor, Richard David Jenkins, laid the foundation stone on 8 July 1858. Local builders David Jenkins, John Davies, and John Thomas of Cilgerran built the new guildhall to the designs of an English architect, Robert Jewell Withers, working in Blue Lias stone from the surrounding countryside. It cost £4,055 and was officially opened on 9 July 1860.

Withers designed the guildhall in the Gothic Revival style — pointed arches, mullioned and transomed windows with hood moulds, gables, a mansard-roofed main hall — but he did so following a very specific set of principles. The art critic John Ruskin had published The Stones of Venice between 1851 and 1853, arguing that the Gothic builders of medieval Italy had achieved their effects through honest craftsmanship and structural truthfulness, and that any modern building worth respect should follow the same rules. Ruskin's ideas had a powerful effect on English architectural debate in the 1850s. Withers's design for Cardigan was reportedly one of the first buildings in the UK to be planned explicitly on Ruskin's principles. The asymmetrical seven-bay frontage, with its five projecting bays for the main hall section and its separate gabled end-bay for the council chamber, was meant to express rather than disguise what was going on inside the building. The corn exchange ran along the ground floor; the great hall sat above it on the first floor.

The Russian cannon arrived in 1871 — sixteen years after Balaclava, eleven years after the guildhall opened, and just within the window when the British public still cared enough about the Crimean War to find such a relic resonant. It sits on a low stone plinth in front of the building. The clock tower, with its pyramid-shaped roof rising above the second bay on the left, was added in the early 1890s by the then-mayor David Davies at his own expense. The local architect Richard Thomas designed it, the local builder John Evans built it, and it was completed in August 1892. The public library opened in the former corn exchange on the ground floor on 6 February 1950 and served Cardigan readers for forty-four years before relocating to the Canolfan Teifi in 1994. The corn exchange space then became an art gallery.

The guildhall ceased to be the seat of local government in 1974, when the enlarged Ceredigion District Council took over. Without its administrative function, the building lost much of its day-to-day purpose. By the early 2000s it needed serious work. A local regeneration company called Menter Aberteifi, supported by a £2.5 million grant from the Heritage Lottery Fund, ran a major refurbishment programme that completed in 2008. The work restored the building's exterior, modernised the services, and turned the great hall on the first floor into a community events space. The ground floor, where the corn exchange had once been, now houses market stalls — a covered market where small independent traders sell food, books, crafts, and clothing six days a week. The guildhall has come back to something close to its original purpose, by accident. The cannon is still there. The clock still works.

The Cardigan Guildhall is small. It is the work of a provincial English architect for a small Welsh town that was already past its commercial peak when the building was commissioned. It would not turn heads in Cardiff or in any English county town with serious Victorian civic pretensions. But it survives, mostly intact, on the same street where it has always stood, doing more or less the work it was built to do. The Russian cannon outside is a strange piece of nineteenth-century international history that has somehow become a piece of nineteenth-century Welsh local history; the clock keeps time over a stretch of Pendre that has not changed shape since David Davies paid for the tower; the market stalls underneath sell to people whose great-great-grandparents bought corn from the same floor. The argument the building makes is quiet, and the argument is that civic pride is not the same as size.