A member of the Rhode Island National Guard, Case was called to active duty on June 14, 1916 and served on the Mexican border as captain of Troop A of the 1st Cavalry Squadron until the unit was mustered out of Federal service in November.

Shortly after the United States entered World War I in April 1917, Captain Case and his troop were mustered into Federal service on July 25.

On August 20, Case's troop was re-organized as Company A of the 103d Machine Gun Battalion which was assigned to the 26th Division.

He was reassigned as Judge Advocate of the 26th Division on January 1, 1918 and as Assistant Provost Marshal for the Services of Supply on February 13.

[US President Franklin D. Roosevelt appointed Case as one of the initial commissioners of the Federal Communications Commission when the agency was set up in 1934 and reappointed him for a full seven-year term in 1938.

In 1945, by-then Senator T. F. Green opposed Case's candidacy for a third term, and President Harry Truman did not renominate him.