What was Franklin Roosevelt’s rank during World War I? July 14, 2020January 28, 2012 by Pamela Landy During World War I (1917-18), Franklin Roosevelt was the assistant secretary of the Navy. Related Answers How much money was raised from war bonds during World War II? When was Franklin D. Roosevelt stricken with polio? How much did the U.S. national debt grow during World War II? What were President Franklin Roosevelt’s “Four Freedoms”? How many American women were employed during World War II? What military ranks did James Stewart and Clark Gable reach during World War II?