What is Insurance Commissioner?

Legal Definition
An insurance commissioner (or commissioner of insurance) is a public official in the executive branch of a state or territory in the United States that, along with his or her office, regulate the insurance industry. The powers granted to the office of an insurance commissioner differ in each state. The office of an insurance commissioner is established either by the state constitution or by statute. While most insurance commissioners are appointed, in some jurisdictions they are elected. The office of the insurance commissioner may be part of a larger regulatory agency, or an autonomous department.

Insurance law and regulation is established individually by each state. In order to better coordinate insurance regulation among the states and territories, insurance commissioners are members of the National Association of Insurance Commissioners (NAIC).
-- Wikipedia
Legal Definition
A public officer in several of the states, whose duty is to supervise the business of insurance as conducted in the state by foreign and domestic companies, for the protection and benefit of policy-holders, and especially to issue licenses, make periodical examinations into the condition of such companies, or receive, file, and publish periodical statements of their business as furnished by them.
-- Black's Law Dictionary