The building is associated with the Irish Catholic community, one of the predominant immigrant founding groups in Ottawa in the early 19th century. The church congregation was founded by a group of Irish parishioners who wanted their own church separate from the predominantly French-speaking Notre Dame Basilica, located a few blocks south.

The church was designed by architect John R. Bowes and is defined by an eclectic mix of Victorian architectural motifs and Gothic Revival features. More basilican than truly cruciform in plan, it is constructed of limestone and has a pitched roof. The distinguishing features of the principal façade are two towers of differing heights. Round arched portals, various window forms, a bulbous spire on the taller of the two towers and bartizans combine to provide a heavily textured, picturesque appearance favoured by Victorians. Located in the Lower Town area, the church is a significant landmark and part of an important heritage area and streetscape.

The Ontario Heritage Trust secured a heritage easement to conserve the building in 1992. The City of Ottawa has also designated it under the Ontario Heritage Act.