Scout is the most obvious choice of protagonist of To Kill a Mockingbird. While her decisions do not directly incite the action of the trial, other choices she makes, such as to spy on Boo Radley, or to confront the men outside the jail, determine the course of the novel. Atticus also tells Uncle Jack that he is defending Tom Robinson because he wants to set a good example for Scout and Jem, so in a sense Scout is indirectly responsible for the action around the trial as well. Over the course of the novel, Scout matures from a child who judges people based on their status, such as unsophisticated Walter Cunningham or reclusive Boo Radley, to a more mature young woman who is able to see the individual inside each person. At the end of the novel, Scout has learned to see beyond her childish preconceptions about Boo Radley and thinks about the world from his perspective. In some ways, the very end of the novel is when Scout first steps into her own as a protagonist. Though Scout’s simplicity and goodness make her an appealing protagonist, her perception of racial issues remains simplistic and childish, which, while appropriate for the character, can be less than satisfying for the reader. 

Another choice for protagonist is Atticus, whose decision to defend Tom Robinson incites the central action of the book and results in the death of two characters. Throughout the book, Atticus’s goal is to raise his children to judge people without prejudice in a town roiled by racism and intolerance. In pursuit of this goal he takes on a case he knows he’s going to lose, in hopes of setting a good example for his children. Thwarting Atticus in this goal is Bob Ewell and other racist members of the community, as well as the flawed justice system itself. As a character Atticus doesn’t change much over the course of the novel – he is an idealistic, determined, and wise father at the beginning of the novel, and ends with the same characteristics intact. However, Scout and Jem’s perception of Atticus changes over the novel, as they see aspects of their father they didn’t know about, such as the fact that he is an excellent marksman, or that he is sympathetic to their cruel and racist neighbor, Mrs. Dubose.