Oklahoma constitution
Article VI: executive power
Section 23

There shall be elected by the qualified electors of the State, at the first general election, a chief officer of said department, who shall be styled "The Insurance Commissioner," whose term of office shall be four years: Provided, That the first term of the Insurance Commissioner so elected, shall expire at the time of the expiration of the term of office of the first Governor elected. Said Insurance Commissioner shall be at least twenty-five years of age and well versed in insurance matters.