[2] St. Thomas is the oldest Catholic parish in Beloit,[3] with roots going back to 1846, when the parishioners were largely Irish immigrants worshiping in the home of Captain Thomas and Lucy Power, where City Hall now stands.

In 1854 the parish built a stone church,[4] in which they worshiped for thirty years until it burned in 1884.

Ward set right to work raising funds for a new building, partly by giving a series of temperance lectures.

James J. Egan of Chicago designed a simply massed rectangular building with a gable roof and a square corner tower, with fine details.

The church was built by masons Marshall and Sweet, carpenters Cummingham Brothers, and stonecutter A.S. Jackson, all from Beloit.