He was chosen by Bishop William Kinsella (1793-1845) who instigated the building of St. Mary's in February 1842.

On Sunday 4 October 1857, St. Mary's had its grand opening, which consisted of a two-and-three-quarter hour ceremony that began at 6.15am.

The cathedral has a cruciform plan and its style is described as ‘Early English Gothic’.

It is situated on the highest point in Kilkenny City and is a significant local landmark.

Its bell in the steeple was made by John Murphy, a Dublin foundry.