The foundation stone was laid in 1892 and construction began in early 1904, with the sanctuary, transepts and nave completed by mid-1907 when the first liturgical mass was held.

A large pipe organ completed the project and in 1919, with all debts dissolved, St Carthage's Cathedral received its solemn dedication by the Apostolic Delegate, Archbishop Cattaneo.

[3] However, when commissioning the works in 2009, the main focus of the project was on roof slates, stained glass windows, and lead downpipes; with completion of the stone steeple ruled out.

[6][7] The Catholic Education Office which is responsible for 46 co-educational schools in the Diocese, is located in Lismore.

[9] The diocese also has a community of Marist Brothers, another of Presentation Sisters and a convent of Carmelite Nuns.