Alabama Code Title 40. Revenue and Taxation § 40-2-41

The Commissioner of Revenue shall be appointed by the Governor and shall hold office at the pleasure of the Governor. He shall be a qualified elector and known to possess high character and knowledge of the general subject of taxation and matters pertaining thereto. He shall not hold another office under the government of the United States or under any other state or of this state, or any political subdivision thereof, during his incumbency in such office and shall not hold any position of trust or profit or engage in any occupation or business the conduct of which shall interfere or be inconsistent with the duties he assumes as Commissioner of Revenue under the provisions of this title;  provided, that no one shall be eligible to serve as Commissioner of Revenue while employed by or financially interested in any public service corporation, nor unless he shall have been a citizen of Alabama for a period of five years and shall be over 30 years of age.