The highest authority in the City of Lahti resides with the City Council. The City Council of Lahti has 102 members elected by the residents. The Council consists of the combined Councils of Lahti and Nastola, as the municipalities merged on 1 January 2016.
The City Board is in charge of the procurements and financial management of Lahti as well as preparing and implementing decisions by the Council. The 13-member City Board works for the interests of Lahti. Mayor Jyrki Myllyvirta, working under the City Board, manages the operations and finances of the City and helps with coordinating officeholder preparations and political goals.
The City has five boards, two divisions under the City Board and three regulatory committees. The organisation of the City of Lahti is based on a division by service department, and the services of the City are organised by Social and Health Services, Educational and Cultural Services and Technical and Environmental Services. Administrative Affairs takes care of the central administration. The City employs more than 6,000 professionals.