After Benjamin N. Cardozo took office as Chief Judge of the New York Court of Appeals in January 1927, O'Brien was appointed a judge to fill the vacancy, and in November 1927 was elected to a fourteen-year term. Ill health compelled him to tender his resignation on December 7, effective December 31, 1939.
After Benjamin N. Cardozo became Chief Judge of the New York Court of Appeals in January 1927, O'Brien was appointed a judge to fill the vacancy and elected for a fourteen-year term in November 1927. Ill health compelled him to resign on December 7, effective December 31, 1939.