He was the United States attorney for the District of Delaware from 1903 to 1916, thereafter returning to private practice in Wilmington in 1930.

He was a captain in the United States Army Ordnance Corps during World War II in 1918.

[1] On June 20, 1930, Nields was nominated by President Herbert Hoover to a seat on the United States District Court for the District of Delaware vacated by Judge Hugh M. Morris.

Nields was confirmed by the United States Senate on July 3, 1930, and received his commission the same day.

He assumed senior status on September 30, 1941, serving in that capacity until his death on August 26, 1943, in Nahant, Massachusetts.