A third storey section of the building was known as St. Patrick Hall, an important meeting place for the Irish Catholic Benevolent Union.
By the 1870s the growing city had a number of larger and more suitable performance venues and the Hall entered a long decline.
The City of Toronto government fully restored the hall in 1967 to mark the Centennial of Confederation (and rebuilt the east wing which had completely collapsed).
A remote detonated explosion, standing in for the groundbreaking of Canada's Wonderland theme park in the York Region town of Maple, took place from the Hall.
The Renaissance Revival was a clear goal of William Thomas, but the Hall reinterpreted the Italination in a vernacular and contemporary manner.
St. Lawrence Hall is designed in a Victorian composition with a French mansard roof due to abundant snowfall in Ontario.