Except as otherwise expressly provided, there shall be elected by the qualified electors of the county a county superintendent of education for each county, who shall, except as otherwise expressly provided, hold his office for a term of four years and until his successor is elected and qualified. He shall, before being commissioned and entering upon the duties of his office, give bond to the State for the use of the county in which he is elected, for educational purposes, in the penal sum of one thousand dollars, except as otherwise provided, with good and sufficient sureties, to be approved by the governing body of the county, conditioned for the faithful and impartial discharge of the duties of his office, and he shall take and subscribe the oath of office prescribed in Section 26, article III of the Constitution of this State, which he shall file in the office of the Secretary of State. When commissioned he shall immediately enter upon the discharge of his duties. His failure to qualify within thirty days after notice of his election shall create a vacancy.