Mahoney was nominated by President Roosevelt on January 11, 1940, to a seat on the United States Court of Appeals for the First Circuit vacated by Judge James Madison Morton Jr. He was confirmed by the Senate on February 7, 1940, and received his commission on February 12, 1940. He assumed senior status due to a certified disability on December 20, 1950. His service terminated on November 18, 1952, due to his death.[1]
^Lapomarda, S.J., Vincent A. (1992). The Knights of Columbus in Massachusetts (second ed.). Norwood, Massachusetts: Knights of Columbus Massachusetts State Council. p. 67.