The Nathaniel Witherell has named John Mastronardi executive director of skilled nursing and short-term rehabilitation facility, which is owned and operated by the Town of Greenwich, CT.

Formerly Administrator of Montefiore/Schaffer Extended Care Center in New Rochelle, NY, Mastronardi started at Witherell on April 27. He replaces Allen Brown who retired last December.

Mastronardi brings over 15 years of experience in operations and healthcare management to the Witherell. He was previously administrator and executive director of Aging in America in the Bronx, NY, and held key management positions at Morningside House, also in the Bronx.

He holds a master of public administration from Pace University and a bachelor’s degree in behavioral science and health Informatics from Mercy College.