The legislative power of the City of Harriman is vested in City Council, consisting of a Board of Aldermen, with the Mayor as presiding officer. Within this framework, the City's residents elect a six-member City Council charged with providing community leadership and developing policies to guide the City Administration's delivery of services.

The City Council appoints the City Manager, who serves as chief administrator of the City and ensures that the Aldermen's policies are properly executed. The City Council also appoints the City Chief Finance Officer, City Judge, and City Attorney.

The Mayor is the Chief Executive Officer of the City and the presiding officer of the City Council. The Mayor shall from time to time, give the City Council information relative to the condition of the city, and shall recommend to its consideration such measures as they may deem expedient for the interests of the City. The Mayor shall take care that the laws of the State and ordinances of the City are respected and enforced within the City.

Harriman City Council members are elected to four-year, staggered terms. The Mayor also serves a four-year term in office.