[1] Mayer was nominated by President William Howard Taft on February 19, 1912, to a seat on the United States District Court for the Southern District of New York vacated by Judge George B. Adams.

He was confirmed by the United States Senate on February 26, 1912, and received his commission the same day.

His service terminated on October 13, 1921, due to his elevation to the Second Circuit.

[1] Mayer was nominated by President Warren G. Harding on September 22, 1921, to a seat on the United States Court of Appeals for the Second Circuit vacated by Judge Henry Galbraith Ward.

[1] After his resignation from the federal bench, Mayer resumed private practice in New York City from 1924 to 1925.