(Answer #1). Andrew Johnson is important in American history for two major reasons. First, he was the first president to be impeached. He escaped conviction and was therefore not removed from office, but he was impeached.Second, he was the president whose actions led to the creation of Radical Reconstruction.. Johnson became president after President ...Answer #1). Andrew Johnson is important in American history for two major reasons. First, he was the first president to be impeached. He escaped conviction and was therefore not removed from office, but he was impeached.