After abruptly resigning from the top job in the Police Department in June, Ms. Sewell will help lead security in Citi Field.
Keechant Sewell, the former New York City police commissioner, has been hired by the Mets.
Nearly five months after she resigned as commissioner, Ms. Sewell will become the senior vice president of security and guest experience for the team, the Mets said in a statement on Thursday.