That would be Franklin Delano Roosevelt. In 1932, Hoover and Roosevelt were competing in the presidential elections. Hoover, a Republican, had already served as president from 1929 to 1933, and he was beaten in 1932 by Roosevelt, a Democrat. Hoover was president during the Great Depression, which Roosevelt blamed him for because of the state of America before and after it.
After doing the ressearch about Johnson's actions, the one that surely brought a huge impact on reconstrution was that he granted amnesty to former Confederate soldiers.