The early mention of the Misfit in the plot adds greatly to the darkly comic irony of this short story. It is important to remember that the grandmother mentions the Misfit in order to try and dissuade her son from going to Florida, and she eagerly seizes upon a newspaper report that suggests the Misfit is headed towards Florida to support her plans to go to Tennessee instead:
Here this felow that calls himself The Misfit is aloose from the Federal Pen and headed toward Florida and you read here what it says he did to these people. Just you read it. I wouldn't take my children in any direction with a criminal like that aloose in it.
Of course, one of the tremendous ironies of the short story is that the grandmother does get her rather selfish wish to go to Tennessee, but she doesn't suspect that this will take her right into the path of the Misfit, and the tragic stories that she reads about in the newspaper are things that she and her family will come to experience themselves. Note, too, that it is typical of the way that O'Connor structures many of her stories: the grandmother, being essentially a very selfish character, doesn't really care about the Misfit. She is only using him to achieve her own selfish goals. However, it is ironic that this leads her to meet him and to confront her own selfishness, and achieve, after a fashion, some form of grace.