Sybil Hart Kooper was a retired justice of the Appellate Division of the State Supreme Court in New York. She was born in Brooklyn in 1925, to a State Supreme Court Justice and Presiding Justice of the Appellate Division, Second Department. She attended Wellesley College and New York Law School and practiced with a specialization in family law. Kooper was eventually appointed to Family Court by Mayor John V. Lindsay. She would preside over significant court cases such as the murder of William Turks. In 1985 she was appointed to the Appellate Division, Second Department by Governor Mario M. Cuomo. After suing the Metropolitan Trial Lawyers Association for denied entry based on her gender, she became its first female member. She also investigated gender biases in the court as a member of the Women in the Courts. She died in 1991 due to breast cancer. She is survived by her husband and four children.