N.Y. Comp. Codes R. & Regs. tit. 8 § 7.3
No trustee or board of education shall contract with a teacher not legally qualified. None of the school moneys apportioned to a district shall be applied to the payment of an unqualified teacher, nor shall the teacher's salary, or any part thereof, be collected by a district tax, unless the time for which such teacher has taught has been legalized by the commissioner. A teacher shall possess or be entitled to a certificate of qualification, or shall possess or be entitled to a provisional certificate, or shall possess a regional credential before the teacher enters into a contract to teach; and before beginning service the teacher shall present the certificate or credential for recording to the city, village or district superintendent in whose jurisdiction he or she is to teach.
N.Y. Comp. Codes R. & Regs. Tit. 8 § 7.3