The City of San Marcos was incorporated on January 28, 1963 and was chartered on July 4, 1994 and operates under a Council/Manager form of government.
As a municipal corporation, the City Council, the city’s chief policy-making body, enacts laws known as ordinances, sets policies known as resolutions and adopts an annual budget. The city manager serves as the city's chief administrative officer and sees to it the council's programs are implemented.
The Mayor and Council Members are elected at-large by the citizens of San Marcos to serve a four-year term and are allowed to serve a maximum of three consecutive terms.
The City Council also oversees a variety of commissions that deal with specific City-related issues. These advisory commission members are appointed by the City Council.