The Church was designed by Thomas Jackson of Waterford and it is in the ecclesiastical style of the Tudor period. Saint Malachy's Church is regarded as one of the finest examples of Tudor Revival churches in Ireland.
Sir Charles Brett stated: It is as though a wedding cake has been turned inside out, so creamy, lacy and frothy is the plasterwork. ('Buildings of Belfast')
The Sanctuary floor is mosaic, the principal colour being blue. At the foot of the Altar is a pelican, a common Christian symbol of sacrifice. Saint Malachy's is, perhaps, best known for its fan vaulted ceiling which is an imitation of the Henry VII Chapel in Westminster Abbey.
The area of the city around Saint Malachy's has been dramatically developed in the last number of years. That, and its age, have led to the deterioration in the condition of the brickwork which has meant that a full scale Restoration Programme began in January 2008 and was completed in 2009.
The Church houses the largest bell in Belfast. Close to the Church stood a whiskey distillery and its owners claimed that the peal of the bell was upsetting the distillation process. Contrary to popular belief the bell was not removed, instead it was wrapped in felt to soften its peal and vibration.