With the arrival of Johnston's Army in 1857, activities at the Social Hall ceased. The soldiers at Camp Floyd, however, soon organized a theater. The Camp Floyd Theater, built of pine boards and canvas, accommodated 200 people. The Germania Singing Club also opened a social hall at Camp Floyd and put on performances in German.

In 1859 a new company, the Mechanics' Dramatic Association, was formed in Salt Lake City. Harry Bowring offered the first floor of his new home for the Theater, which became known as Bowring's Theater. The theater was located on 100 South between 300 and 400 East. Brigham Young soon decided that the Saints should have a first-class Theater, and excavations on the corner of 100 South and State streets began in July 1861.

The Salt Lake Theater, finished in March 1862, was the largest structure yet built by the Saints and cost $100,000. William H. Folsom was the architect of the exterior, which was Doric in style. E.L.T. Harrison, an architect from London and recent convert*, modeled much of the interior after the London Drury Lane Theater. Building supplies came from the now-disbanding Camp Floyd and the wreckage of government wagons on the trail.

The theater was dedicated with a prayer by Daniel H. Wells, and an address by Brigham Young. Over 1,500 people crowded the theater for the opening, and many continued to come for later performances. Dubbed the "Cathedral in the Desert," the theater became a neutral ground for Mormons and non-Mormons, although it was controlled by the Mormons.