(for reversal). Because the definition of "teacher” includes "all certificated persons”, MCL 38.71; MSA 15.1971, Bode, being such a person, is entitled to the protection of the teach*524ers’ tenure act upon satisfactory service of the probationary period.
During his first two years of employment as a superintendent in Clintondale, he was subject to the provisions of MCL 38.81; MSA 15.1981, which read in pertinent part:
"All teachers during the first 2 school years of employment shall be deemed to be in a period of probation.”
The language in this section is mandatory ("shall”) and cannot be made ineffective by contract of the parties. Therefore, even though Bode labored under a contract denying him tenure in his superintendent position in Clintondale, that contract cannot be construed to deny service of the probationary period. The contract simply had no effect on service of probation. I do not share the view that it was illegal.
Bode served two years in Clintondale without receiving notice that his work was unsatisfactory, MCL 38.83; MSA 15.1983, and thereby achieved continuing tenure in Clintondale.
Upon his subsequent employment in Roseville, Bode needed to serve only one year of probation in order to attain tenure in that district. MCL 38.92; MSA 15.1992. His employment by Roseville under an oral contract as an administrative assistant from March, 1970 until July of that year, did not give him tenure as a superintendent. Nor did his employment as "acting superintendent” under the one-year contract from July, 1970 to June, 1971. Neither period of employment completed the probationary period in that classification. Such employment did, however, constitute the satisfactory completion of a one-year period of probation in *525Roseville entitling Bode to a tenure contract as a classroom teacher.
For these reasons, I agree that Bode is entitled to tenure as a classroom teacher in Roseville.
Levin and Blair Moody, Jr., JJ., concurred with Kavanagh, J. Williams, J.(for reversal). This case concerns the question whether one serving as a school superintendent can acquire tenure as a teacher. Since the teachers’ tenure act definition of "teacher” includes "superintendent” inter alia, service as a superintendent can qualify one for teacher tenure. We hold that plaintiff Bode’s service as superintendent was of such length and character as to qualify him for tenure as a teacher and the privileges thereof. The Court of Appeals is reversed.
I. Facts
Plaintiff Bode served in various school districts as a classroom teacher from 1950 to 1955 and as a principal from 1955 to 1958. During this time he was not eligible for tenure, because at that time there was no tenure unless the school system opted for it,1 and none of his school districts had.
More significantly, after the tenure act became mandatory, plaintiff served as superintendent in Leslie from 1962 to 1966. He next served as superintendent in Clintondale from 1967 to 1970, when he resigned. Finally, after serving part of a year on a day-to-day basis in the Roseville School District, plaintiff was appointed as of July 1, 1970 as *526acting superintendent with a one-year contract. This was followed by a two-year contract as superintendent commencing July 1, 1971, but with a provision as follows:
"4. The Superintendent of Schools shall not be deemed to be granted continuing tenure by virtue of this agreement.”
On October 10, 1972, the school board assigned plaintiff to duties as acting superintendent. Plaintiff served as a special consultant until his employment contract expired. On or about February 7, 1973, Bode received notice he would not be employed after June 30, 1973.
In October, 1972, plaintiff had petitioned the State Tenure Commission to find he had tenure as superintendent and that his reassignment as acting superintendent with duties as special consultant was improper. On June 11, 1973, the tenure commission held that the school board’s removal without notice and hearing was contrary to the tenure act, found that plaintiff had tenure as a superintendent, and ordered plaintiff restored as "Superintendent” but leaving to the school district his exact duties. The circuit court reversed the tenure commission. The Court of Appeals affirmed the reversal in an unpublished per curiam opinion. We granted leave to appeal, 399 Mich 898 (1977).
II. Pertinent Tenure Act Provisions
MCL 38.71; MSA 15.1971 provides:
"The term 'teacher’ as used in this act shall include all certificated persons employed for a full school year by any board of education or controlling board of any public educational institution.”
*527It is clear from this statutory language that a superintendent can be a teacher under the act. The tenure commission has so held:
"We previously have held that article I, § 1 of the tenure act includes superintendent within the term teacher, Anderson v Westwood Community School District [State Tenure Commission, Docket No. 70-13].”
MCL 38.81; MSA 15.1981 provides:
"All teachers during the first 2 school years of employment shall be deemed to be in a period of probation.” (Emphasis added.)
This provision is not limited to classroom teachers and would apply to any one defined as a "teacher” by the act.
The following sections of the tenure act provide that a teacher completing the required years of probation has tenure unless notified otherwise by the controlling board.
MCL 38.91; MSA 15.199Í states:
"After the satisfactory completion of the probationary period, a teacher shall be employed continuously by the controlling board under which the probationary period has been completed, and shall not be dismissed or demoted except as specified in this act.”
MCL 38.83; MSA 15.1983 states:
"At least 60 days before the close of each school year the controlling board shall provide the probationary teacher with a definite written statement as to whether or not his work has been satisfactory. Failure to submit a written statement shall be considered as conclusive evidence that the teacher’s work is satisfactory. Any probationary teacher or teacher not on continuing con*528tract shall be employed for the ensuing year unless notified in writing at least 60 days before the close of the school year that his services will be discontinued.”
The act also places a limit on the number of years a teacher with tenure may be required to serve in another school district to fulfill the probation requirement.
"If a teacher on continuing tenure is employed by another controlling board, he shall not be subject to another probationary period of more than 1 year.” MCL 38.92; MSA 15.1992.
MCL 38.172; MSA 15.2054 prohibits a teacher from waiving any rights and privileges:
"No teacher may waive any rights and privileges under this act in any contract or agreement made with a controlling board.”
Under MCL 38.91; MSA 15.1991, a superintendent may waive tenure rights as a "superintendent”, but only after completion of tenure as a teacher.
"If the controlling board shall provide in a contract of employment of any teacher employed other than as a classroom teacher, including but not limited to, a superintendent, assistant superintendent, principal, department head or director of curriculum, made with such teacher after the completion of the probationary period, that such teacher shall not be deemed to be granted continuing tenure in such capacity by virtue of such contract of employment, then such teacher shall not be granted tenure in such capacity, but shall be deemed to have been granted continuing tenure as an active classroom teacher in such school district. Upon the termination of any such contract of employment, if such controlling board shall not re-employ such teacher under *529contract in any such capacity, such teacher shall be continuously employed by such controlling board as an active classroom teacher.” (Emphasis added.)
III. Application to Appellant Bode
Bode has been in the field of education for 28 years, and a teacher under the act for 14 years. From 1950 to 1964, when the act became mandatory, he served in school districts which had not elected to come under its provisions.
When the act became mandatory he was in the middle of a two-year contract at Leslie, Michigan. He was not reappointed in Leslie, and, because of the nature of the grandfather clause,2 did not qualify for tenure.
Bode’s first position entirely under the act, after it became mandatory, was with the Clintondale School District from 1967-1970, as a superintendent. The rule is that at the end of the second year a teacher is deemed to have successfully completed probation and obtained tenure unless notified otherwise according to the provisions of MCL 38.83; MSA 15.1983 and MCL 38.81; MSA 15.1981. Bode was not notified that his work was unsatisfactory and should have obtained tenure.
But it is claimed that Bode’s contract with the *530Clintondale School District containing a provision excluding tenure precluded obtaining tenure. However, the tenure act provides that a contractual waiver by a teacher in an administrative position can only be "made with such teacher after the completion of the probationary period”. MCL 38.91; MSA 15.1991. Since Bode had never achieved tenure, the waiver was illegal and of no force and effect. Consequently, plaintiff obtained tenure as a classroom teacher after his first two years of service without notification his work was unsatisfactory. Therefore, we agree with the tenure commission that
"while Bode did not gain tenure as a superintendent during his employment with the Clintondale School District, he did gain tenure in position as a teacher having served for the statutory two years probationary period; * * *.”
When Bode moved to Roseville, his service as acting superintendent for one year satisfied the requirement of a probationary period. MCL 38.92; MSA 15.1992. He was not notified that his work was unsatisfactory, MCL 38.83; MSA 15.1983, and therefore received tenure as a teacher.
The tenure commission, however, held that Bode received tenure as a superintendent while in the position of acting superintendent. We disagree. Plaintiff could not acquire service toward tenure as a superintendent, because the resolution appointing him as acting superintendent clearly indicated that the board considered the superintendent’s position still under search.
Bode had tenure when he began the contract for superintendent effective July 1, 1971. He waived *531his right to tenure in the administrative capacity but not as a classroom teacher.
IV. Conclusion
We find first that a teacher serving as a superintendent can acquire tenure as a teacher; second, that Bode completed a two-year probationary period in the Clintondale School District and acquired tenure as a teacher, since he received no notice that his work was unsatisfactory and since the waiver proviso he worked under could not apply until after he received tenure; third, that Bode completed a one-year probationary period with the Roseville School District and received tenure there as a teacher.
We reverse the Court of Appeals.
The teachers’ tenure act did not become mandatory until 1964,
"This act shall apply to all school districts of the state.” MCL 38.151; MSA 15.2051, as amended by 1964 PA 2, § 1.
"Provided, That any teacher under contract at the time this act becomes effective who has previously rendered 2 or more years of service in the same school district shall be granted continuing tenure immediately upon reappointment by the controlling board: Any such controlling board by unanimous vote of its members, however, may refuse to appoint a teacher who has rendered 2 or more years service in the school district under its control. In the event the vote against reappointment of such teacher is not unanimous the controlling board shall deem such teacher as on continuing tenure with full right to hearing and appeal as provided in article 4 and article 6 of this act: Provided further, That the controlling board, after this act becomes effective, may place on continuing tenure any teacher who has previously rendered 2 or more years of service.” MCL 38.81; MSA 15.1981.