In following the teachings of Gandhi, Dr. Martin Luther King, Jr. practiced and advocated non-violent resistance. If Dr. King used methods that broke the stated law at the time, can he be considered a hero?

It depends on your definition of hero, I guess. The fact that Gandhi and MLK did not use force to advocate for their opinions was mature and moral. They did not give up the first time. But maybe if the cause is correct, one might have to break the stated law, and become a hero.