Franklin D. Roosevelt is typically seen as one of the greatest presidents in US history while Herbert Hoover is seen as one of the worst. This is probably not fair to Hoover, but it is how the two are seen. FDR is seen as much greater than Hoover because he was more willing to experiment to end the Great Depression and because he was better than Hoover at communicating with the people (and because he also led the US through WWII).
Herbert Hoover did realize that the Great Depression called for government action. For example, he had the federal government spending $500 million per year on public works projects by 1932. He also created the Reconstruction Finance Corporation to lend government money to businesses. However, he was not willing to do as much as FDR was. Hoover did not believe that the government could or should give money to individuals for relief (in essence, welfare payments). He thought that the private sector should be in charge of taking care of people who had been impoverished by the Depression. He thought that it was a bad idea for the government to run deficits to allow it to spend more to help end the Depression.
Roosevelt, by contrast, was willing to do more things to try to end the Depression. He was willing to expand the role of government tremendously. He spent much more money than Hoover on public works. He had the federal government give out relief funds to individuals. While he did not like deficit spending, he was willing to engage in it since he thought it was necessary. He was even willing to have the government get involved to the extent of paying farmers not to plant crops and setting up the Social Security system. In short, FDR was willing to do whatever it took to end the Depression. In addition, he was a more skilled politician than Hoover was. Through his “fireside chats,” FDR was able to make people have confidence in him and believe that he cared about people like them. Hoover had never been able to accomplish this. In these ways, FDR was different from Hoover and those differences have led to the extreme difference in the way these two presidents are perceived.