Mich. Comp. Laws § 38.71

Sec. 1. (1) The term "teacher" as used in this act means a certificated individual employed for a full school year by any board of education or controlling board. (2) An individual who is not certificated but is employed for a full school year pursuant to section 1233b of the revised school code, Act No. 451 of the Public Acts of 1976, being section 380.1233b of the Michigan Compiled Laws, or is employed pursuant to an annual vocational authorization or a temporary approval, as defined in state board rule, is considered to be a teacher for the purpose of serving the probationary period under article II, but such an individual is not considered a teacher for the purpose of continuing tenure under article III until he or she becomes certificated. (3) An individual employed as a teacher in a public school academy established under Act No. 451 of the Public Acts of 1976, being sections 380.1 to 380.1852 of the Michigan Compiled Laws, is not considered a teacher during that employment for the purpose of continuing tenure under article III. However, an individual described in section 1(4) of article III is a teacher for the purpose of retaining continuing tenure as described in that section. (4) Teacher does not include an individual whose teaching certificate has expired or has been suspended or revoked.