He went on to study in Paris, before returning to Cornell University, where he was responsible for producing a detailed, annotated catalogue of Cornell's extensive collection of Dante's works.

[2][3] During World War I, while on the staff of the Library of Congress, Koch played an instrumental role in ensuring that scientific publications from Germany and other combatants continued to be available to American researchers.

He also organized programs to provide books to American soldiers in the trenches.

He was a translator of Italian poetry and essays; scholar of Dante; widely published on issues of libraries and public education from the 1910s to the late 1930s.

In 1940 he received the Cross of the Legion of Honor from the French Government, for his lifelong work in translating, promoting, and enhancing the appreciation of French literature in the United States.