Who is Johnny from Meridian: A Novel and what is their importance?

Johnny is a poor, black man who quit his job at a copper factory because the factory owners wanted to shut off his only window. He collects dirty and slimy pieces of newspaper to roll into kindling, which he sells for three cents or a nickel. Johnny has a son, who he can't afford to buy shoes for, and he has a wife Agnes, who is dying. However, because of Meridian's kindness and acceptance, he registers with her to vote after his wife dies.