Designed by the Buffalo firm of Esenwein & Johnson which also designed the Temple of Music, the Service Building was the first completed on the grounds. It was two stories high, light yellow in color, 150 by 100 feet, and occupied a location near the West Amherst Gate on the Elmwood side of the grounds. It was also adjacent the the Emergency Hospital. The original design featured an open central court to provide natural lighting for offices, but that was enclosed to provide additional office space.
As its name implies, the Service Building was the administration center for the Exposition. The architects and construction contractors labored there beginning in 1900, the Exposition Company had offices and a board room, the Directors had their offices and staff on site and, by June 1901, the Exposition Police had a two-cell jail in the building.
Henry Nicholls was an employee of the Treasurer's office in 1901 and recalled the layout of the building:
"The entrance to the Service Building was through an alcove in the center of the front of the building. The Treasurer's office occupied the front and whole ground floor on the left of the entrance; the Police Department was on the right side of the entrance with the Emergency Hospital at the back. The President's, Secretary's, and Board of Director's offices were on the second floor."
The Service Buildling was also among the last buildings to be demolished, being useful to the Chicago Housewrecking Company as their headquarters during the dismantling of the buildings. And it yielded a treasure in September, 1902, when the section of flooring upon which President McKinley stood when shot was discovered hidden away.