Built around 1602, the Bull Inn was a gable-fronted building stretching approximately 17 metres north to south and 6.5 metres east to west, crowned with a stone chimney at its apex. The facade featured a central doorway flanked by three-light flat-headed windows on either side, all adorned with distinctive hood-mouldings. An 1841 drawing by Graves captured the building when the original central doorway had already been blocked up and a new entrance created to the west, likely by breaking through one of the original windows.

The first floor displayed two two-light windows with a pair of stone plaques between them that tell the building's story. One bore the date 1602 along with 'Insingnia Roberti Jose', whilst the other carried the Latin inscription 'Bulles Inne: Nomen huius faedi dicitur', which translates roughly to 'Bull Inn; the name of the house is called'. The attic level featured two single-light windows, maintaining the hood-moulding detail found throughout the structure. By the late 17th century, however, the inn had fallen into disrepair and remained in a ruinous state for nearly two centuries.

Today, only fragments of this once-impressive building survive. When Bull Alley underwent widening in 1862, the dangerous upper portions were demolished, leaving just the ground floor walls. The eastern wall stands about 4.5 metres high and runs for 15 metres, featuring a cut-stone, square, chamfered window at ground level. The western wall survives to about 2.5 metres in height with small portions of rear returns visible on both sides. Cut limestone quoins mark the northeast and southeast corners, and internal rebates measuring about 1.7 metres high can be seen on both the eastern and western walls; these architectural details offer glimpses into the building's original construction and the skilled craftsmanship of early 17th century Kilkenny.