Which President led the country during both the Great Depression and World War II?

Franklin Roosevelt is the correct answer because he served as the President of the United States from 1933 to 1945, which encompassed both the Great Depression and the majority of World War II. Roosevelt's administration played a critical role in addressing the economic crisis brought on by the Great Depression through the implementation of the New Deal, a series of programs aimed at recovery, relief, and reform. His leadership during World War II included significant decisions regarding military strategy, alliances with other countries, and mobilization of the American economy for war efforts, significantly shaping the course of American history during this pivotal period.

Other individuals mentioned did not serve during both events; Harry Truman succeeded Roosevelt in 1945, Woodrow Wilson's presidency preceded the Great Depression and World War II, and Lyndon Johnson’s term came after both events. Thus, they are not associated with leading the nation through those particular crises.