The city Council members are representatives of citizens elected by Common, Equal, Direct, and Secret elections. The term of office is four years. The Cheonan City Council is composed of 25 members.

A chairman and one deputy chairman are each elected by secret ballot from among the Council members, and the term of office is two years.
The chairman represents the Council, organizes the proceedings, and oversees the affairs of the Council, and the deputy chairman acts on behalf of the chairman in case of an event.

The committees are established in response to the executive body's administrative organization. A Standing Committee to review and process agenda items and petitions under its jurisdiction and a Special Committee to review and handle specific issues may be established. The Cheonan City Council consists of five standing committees, and a special committee is established by resolution of the plenary session if necessary.

The Council Secretariat currently consists of 34 (capacity) staff, including the General Secretary, to handle the Council's affairs.