During the First World War, Stearns served as a first lieutenant with the Sixteenth Infantry, First Division, and at the General Headquarters of the American Expeditionary Forces in France, where he served as assistant military attaché from November 27, 1917, until discharged August 5, 1919.

He received the Silver Star and Purple Heart decorations in recognition of his service.

Returning to the United States, Stearns was Librarian of the College of the Holy Cross in Worcester, Massachusetts, from 1925 to 1930.

A confidential 1943 analysis of the House Foreign Affairs Committee by Isaiah Berlin for the British Foreign Office described Stearns as[1] One of the liberal Republicans who supported the Administration's foreign policy on all major measures, and is reported to be in the Willkie camp, although likely to go along with the Democratic majority on the committee; unlikely to be much of a force, being a kindly old derelict rather than a man of parts.

This article incorporates public domain material from the Biographical Directory of the United States Congress