The main role of a county commissioner is to make policy for his county, which includes determining long-term goals and the means of achieving them. Additionally, he is required to identify the development course of the county and use the budget as a tool to shape the policies.
As part of a board of commissioners, a county commissioner exerts power through the appropriation of funds intended for all county activities, including the building and maintenance of county roads, implementing state and federal mandates, authorizing payments owed by the county, and managing county properties and funds.
By controlling the budget, county commissioners determine the limits of spending with regard to every county program. They are typically required to adopt a new budget on a yearly basis, although it can be done biennially if the county opts for it.
County commissioners are also in charge of land-use policy, particularly in bigger counties with large urbanized areas. Together with citizens, they determine policies that seek to address the county's environmental and land-use issues while managing growth.
County commissioners serve as chief executives within their organizations, making them responsible for the implementation of policies in addition to setting them. Although the executive roles vary depending on the county’s goals and needs, they are typically determined by historical tradition or the skills and the experience of a particular county commissioner. In concert with the board of commissioners, a county commissioner is in charge of hiring and supervising the management staff that runs day-to-day affairs.