Mich. Comp. Laws § 388.401
From and after September 1, 1935, it shall be unlawful for any citizen of the United States to serve as a teacher, instructor or professor in any state educational institution or any educational institution supported in whole or in part by public funds, or in any junior college, college or university of this state or any junior college, college or university whose property, or any part thereof, is exempt from taxation unless and until he or she shall have taken and subscribed the following oath or affirmation:
"I do solemnly swear (or affirm) that I will support the constitution of the United States of America and the constitution of the state of Michigan, and that I will faithfully discharge the duties of my position, according to the best of my ability."
The oath required by this section shall be notarized and transmitted to the superintendent of public instruction, who shall file it in his office, where it shall be subject to public inspection. It shall be unlawful for an officer, person or board having control of the employment, dismissal or suspension of teachers, instructors or professors in any such educational institution, junior college, college or university to permit a person to serve in any such capacity therein in violation of the provisions of this section. This section shall not be construed to require a person to take such oath more than once during the time he or she is employed in the educational institutions in this state, though there be a change in the title or duties of the position: Provided, however, That this requirement shall not be construed as prohibiting such officer, person or board from employing for limited periods instructors or lecturers who are citizens of foreign countries.
MCL 388.401