Ohio Rev. Code Ann. § 5703.07

The tax commissioner shall give bond, conditioned according to law, payable to the state, in such penal sum as is fixed by the governor, with surety to be approved by the governor. Such bond and oath of office shall be filed in the office of the secretary of state. Except as otherwise authorized in section 108.05 of the Revised Code, the tax commissioner and each employee of the department of taxation shall devote his entire time to the duties of his office, and shall not hold any position of trust or profit or engage in any occupation, employment, or business interfering with or inconsistent with his duty as commissioner or an employee, or serve on or under any committee of any political party.