This first clock was placed on top of the store at a cost of $2,000. At the time, the clock was said to be one of the most accurate in the United States. It began operations in November 1864, and everyone who donated more than $25.00 was given a membership in the Dubuque Town Clock Company, which owned the clock.
On May 25, 1872, several people noticed cracks forming in the walls of the store building. Within a few minutes both the clock and the John Bell store collapsed, killing a child and two women who were inside the store at the time.
An investigation into the matter reported that the foundation of the Bell Store was not sufficient to handle the clock's weight, which was nearly 3,500 pounds (1,600 kg). It was also reported that subsequent construction next door was the primary cause of the accident.
The new clock was accurate to within two seconds each week. For a number of years, the clock had a mechanical movement. Two employees spent an hour and a half winding cranks that were attached to the weights, which would allow the clock to operate for one week.
In 1927, the clock was electrified by Interstate Power Company when a new Seth Thomas movement was placed in the clock. Western Union then synchronized the clock.
The Durrant Architecture firm of Dubuque designed a pre-caast four-column pedestal that was then placed in the plaza. The actual tower was brought to the site on Feb 12, 1971, and bolted to the pedestal. The faces of the clock were placed at the new location on Feb 16, 1971. Afterwards the cupola was placed at the new site, which completed the move. After the reassembly was complete, the clock stood about 108 feet above the street, which was about two feet taller than at its previous location.
The move helped increase the visibility of the Town Clock, where it now served as the centerpeice at special events held at Town Clock Plaza. Otherwise, most of the traffic had moved out to the west end of the city. Main street had become an office park.
In 1989, concerns were voiced about vibrations made by loud music and dancers possibly causing damage to the pedestal or the clock. The city studied the problem and stated its confidence that the Town Clock was structurally sound.