The first appointment of an individual to a position similar to that of today's local government manager occurred in 1908 in Staunton, Virginia, where a "general manager" was employed to oversee the administrative functions of the municipality. The first formal adoption of the council-manager plan took place in Sumter, South Carolina, in 1912. The following year, Westmount, Quebec, adopted the plan and so introduced the council-manager form of government to Canada. In 1914, Dayton, Ohio, accepted the council-manager plan and became the first municipality of substantial size to operate under the new form of government. Sixteen years later, Durham County, North Carolina, became the first county to institute a form of government that embodied the concept of professional management.

The City Managers' Association, as it was then called, held its initial meeting in 1914 at a time when only 32 local governments in the United States and Canada had adopted the council-manager plan. The meeting was held in Springfield, Ohio, at the invitation of O. E. Carr of Cadillac, Michigan, and M. H. Hardin of Amarillo, Texas. Hardin, who had recently been appointed to his first position of professional management, felt the need to share his experience and information with the small group of his fellow professionals.

ICMA, from its inception in 1914, has continued to serve a number of essential functions for professional local government management executives. In so doing, the association has improved the quality of local government in which its members serve. As the number of local governments adopting the council-manager form of government has grown, so has the ICMA membership, in terms of both numbers and professional knowledge and skills.

The council-manager plan grew steadily from 1914, slowed only by the difficulties of war and depression. By 1918, there were 100 local governments with the council-manager plan. At the 1924 annual conference in Montreal, the association adopted its first code of ethics, formally labeled "The City Manager's Code of Ethics," and changed its name to the International City Managers’ Association. In 1930, the total number of council-manager communities had increased to 400; and since 1945 the rate of increase has averaged 50 places annually, except for record years 1973 and 1976. (In 1973 there was an increase of 159 local governments and in 1976, 133 were recognized.) By December 1985, ICMA had verified the existence of the plan in 2,563 U.S. local governments. The number of local governments with the council-manager form continued to grow throughout the 1980s and into the 1990s. Today, there are 3,003 ICMA-recognized local governments operating under the council-manager form of government in the United States.

During the 1960s, the profile of local government began to show significant changes. Not only were complex new problems created, but variations in organizations and structure became evident. Some cities, towns, and counties began providing for an appointed official responsible for overall administrative affairs without adopting the council-manager plan as it was originally conceived. Likewise, the development of councils of governments and regional councils brought new and innovative structures to local government. It became obvious to ICMA that, in many cases, the positions being developed did not significantly vary from the role of the traditional professional positions provided for in the council-manager form of government.

In July 1969, the International City Managers' Association changed its name to the International City Management Association and began the process of recognizing local governments that provide for positions of professional management while retaining a form of government other than the council-manager plan. To distinguish them from those recognized as council-manager communities, these newly recognized places were designated "general management" communities. Criteria were established for recognition and the individuals in these local government management positions were made eligible for Corporate membership in ICMA. More recently, in 1986, ICMA completed the same process for recognizing state/provincial associations of local governments.

In May 1991, members voted to change ICMA's constitutional name to the International City/County Management Association, reflecting the membership of the association and recognizing the evolution in county government professionalism.