[2] On December 12, 2018, Bishop Peter Hundt of the Roman Catholic Diocese of Corner Brook and Labrador was appointed archbishop of St. John's.

The Basilica-Cathedral of St. John the Baptist is built in the form of a Latin cross and in the Lombard Romanesque style of a Roman basilica.

It was designed for Bishop Michael Anthony Fleming by the architect of the Danish government, Ole Joergen Schmidt, resident at Altona on the Elbe (Hamburg) though Fleming also had some plans prepared by the distinguished Irish architect John Philpot Jones of Clonmel, County Tipperary, Ireland, and also consulted with James Murphy, a native of Dublin, Ireland, on plans for the cathedral.

Construction was initially supervised by the Waterford contractor Michael McGrath, but later superintended by stonemason and sculptor James Purcell of Cork, Ireland, who also designed and built a small wooden church, Christchurch, at Quidi Vidi near St. John's.

The Basilica-Cathedral of St. John the Baptist is unusual among North America's 19th century public buildings in that it was constructed using limestone and granite imported from Galway and Dublin, Ireland, as well as 400,000 bricks from Hamburg, as well as local sandstone and Newfoundland bluestone quarried from St. John's and Kelly's Island in Conception Bay, giving the Cathedral its characteristic grey colour.

[3] The St. John's Basilica-Cathedral was contemporary with and part of the great boom in church construction which surrounded the era of Daniel O'Connell and Catholic emancipation in Ireland and Newfoundland.

[1] The Basilica was designated a National Historic Site of Canada in 1983, to recognize its architectural uniqueness as one of the earliest North American examples of the Romanesque revival style, and its central role as the spiritual and cultural home of Newfoundland Roman Catholics.

In 2021, Diocesan officials announced that the Basilica was among properties being assessed for potential sale to compensate men who were sexually abused at the former Mount Cashel Orphanage.

The total capacity of the Basilica is around 2,500 people, though during the visit of Pope John Paul II in September 1984, 3600 educators gathered in the Basilica-Cathedral to greet the Roman Pontiff.

[11] The Basilica-Cathedral contains twenty-eight stained glass windows which adorn the upper walls (clerestory) and are of English and French workmanship.

The Altar of Sacrifice, which stands at the front of the Sanctuary, enshrines one of the most revered and important pieces of statuary in the Basilica, The Dead Christ, sculpted in Carrara marble by renowned Irish neoclassical sculptor John Hogan in 1854.