In 1905, the State Civil Service Law was passed and the Civil Service Commission was created. Initially, the State Civil Service Law applied only to welfare institutions, penal institutions and 17 charitable institutions. The Commission's jurisdiction extended to approximately 2,200 employees. The Commission's responsibilities included the testing and appointment of applicants to a wide variety of positions within these institutions. The Commission also conducted investigations and hearings regarding disciplinary matters.

In 1911, the Commission's jurisdiction was extended to the entire state of Illinois and hearings for dismissals became mandatory. In 1917, the Buck Amendment was passed which limited dismissal hearings to cases involving racial, political or religious discrimination. In 1939, the Buck Amendment was repealed and two years later compulsory hearings on discharges were eliminated with hearings only upon the request of the aggrieved employee.

However, problems arose in applying the 1905 State Civil Service Law to a society and government that bore witness to inventions ranging from the tungsten filament light bulb to the hydrogen bomb i.e. rules and standards designed for testing and appointing a wagon maker or seamstress were ineffective for a society and state government that needed qualified electricians and automobile mechanics.

In 1951, the Union League – one of the organizations instrumental in getting the State Civil Service Law adopted in 1905 – led a movement that created the legislative Commission to Study State Government Personnel Administration. Its purpose was to address the shortcomings of the 1905 State Civil Service Law.

After extensive research and analysis, the Commission to Study State Government Personnel Administration proposed the Illinois Personnel Code and the creation of a Department of Personnel under the executive branch. At the time, this proposal was ambitious, innovative and would give the State of Illinois a thoroughly modern system well in advance of the personnel systems of other states. Through labor force analysis, position classification, wage/rate studies and other techniques, this system would create: uniform working conditions, uniform starting salaries, uniform salary increases, the faster filling of vacancies, the ability to create and/or fill positions necessary to keep pace with rapidly changing technologies, a more reasonable and equitable distribution of work load, and allow for the recognition of the accomplishments of the State's workers.

In 1955, Governor William Stratton signed the legislation and, in 1957, the Illinois Personnel Code took effect.

This legislation had a profound affect on the role of the Civil Service Commission. No longer would the Commission be the central personnel agency responsible for examining and appointing applicants to positions within state government. Rather, after the Personnel Code took effect, the Commission became responsible for approving or disapproving certain policies of the Director of Personnel (later known as the Director of Central Management Services), hearing employee appeals, and directing compliance with the Personnel Code and Rules in the event of a violation.

In essence, the Commission became a “watchdog” for state government and, to this day, this responsibility has not changed. Tested for over 50 years since the passage of the Illinois Personnel Code, the independent, bipartisan Civil Service Commission, supported by a dedicated staff, has remained steadfast in its role: to ensure that the employees and citizens of the State of Illinois are afforded the rights and protections set forth in the Personnel Code and the Personnel Rules.