Pursuant to CPLR 1024, "[a] party who is ignorant, in whole or in part, of the name or identity of a person who may properly be made a party, may proceed against such person as an unknown party by designating so much of his name and identity as is known. If the name or remainder of the name becomes known all subsequent proceedings shall be taken under the true name and all prior proceedings shall be deemed amended accordingly." In order to be effective, a summons and complaint must describe the unknown party in such a manner that the John Doe would understand that he is the intended defendant by a reading of the papers. An insufficient description subjects the John Doe complaint to dismissal for being jurisdictionally defective. Parties may not resort to the John Doe procedure unless, prior to the running of the statute of limitations, they exercise due diligence to identify the defendant by name and, despite such efforts, are unable to do so. Any failure to exercise due diligence to ascertain the John Doe's name subjects the complaint to dismissal as to that party.
M.C.-B v. County of Suffolk, NY Slip Op 01758 (2d Dep't March 25, 2026)
