John Singer is the focal point of the other four main characters in The Heart Is a Lonely Hunter. Chapters narrated from Singer's point of view open the and close the first and second parts of the novel. McCullers's writing in these chapters is understated, simplistic, and largely expository, and the tone is calm. The deaf-mute Singer is a silver engraver at a local jewelry store; for ten years he has lived with his close friend Spiros Antonapoulos, another deaf-mute. Singer never seems to realize that he puts almost all of the effort into his friendship with Antonapoulos, but he is happy in this obliviousness. After Antonapoulos is taken away to an insane asylum at the end of Part One, Singer grows very sad and lonely and moves in as a boarder with the Kelly family.
Part Two of the novel chronicles the other characters' increasing dependence upon Singer. Each of them creates his or her own individual conception of who Singer is; because Singer himself cannot speak, he cannot refute or disillusion them. Singer demonstrates one of McCullers's main themes and one of her counter- themes, as he plays one role with Antonapoulos and another with the four other main characters. Singer's devotion to Antonapoulos is McCullers's means of exploring the human struggle to be loved and to express oneself. On the other hand, Singer is an object of such adoration and devotion from the other characters; in this sense he represents the counter-theme that any manmade god or object of worship is inevitably an illusion.
Mick, with her rebellious and courageous spirit as she moves from childhood into adolescence, is the other strong focal point of the narrative—indeed, though Singer is the focus, it is arguable that Mick is the protagonist. There are more chapters devoted to Mick's point of view than to any other character in the novel, perhaps because her character is somewhat autobiographical of McCullers herself. Like Mick, McCullers had serious ambitions of becoming a concert pianist when she grew up. Mick's attachment to music is important not only as a defining character trait but also because McCullers' musical sensibility shapes the entire structure of The Heart Is a Lonely Hunter; indeed, she once referred to the book as a three-part fugue. Throughout the novel, music symbolizes Mick's energy and her pursuit of beauty; she stores it in the "inner room" of her mind, to which only she and Singer have access. Mick's plans to build a violin from scratch, for example, arise from her "inner room." Consequently, her frustration when the violin does not work is more violent than if the idea had been conceived in her "outer room"—the part of her that she allows to interact with the outside world.
Mick is the most positive and hopeful character in the novel. The fact that Mick is a child at the beginning of the novel provides McCullers the opportunity to portray the funny and poignant moments that accompany Mick's coming of age. At her worst, Mick frightens her little brother Bubber into running away after he accidentally shoots Baby in the head with a BB gun; at her best, she heroically offers to quit school so that she can work at Woolworth's to help her poverty-stricken family. At the end of the novel, Mick's final words indicate to us that her inner world remains intact and that she will continue to fight to achieve her ambitions.
Biff Brannon is one of the more bizarre characters in the novel. Like Singer, he is distanced, observant, and quiet. However, none of Biff's observations cohere into any greater insight or concept of humanity; instead, they stand as isolated, unconnected fragments that offer us only puzzling and contradictory impulses that are never satisfactorily explained. When we sees Biff interact with his wife, Alice, at the beginning of the novel, it is clear that the two do not feel any great love for one another after fifteen years of marriage. We also learn that Biff is impotent, though we are never told if this condition is just a problem he has in his relations with Alice or whether it extends to other women as well. Throughout The Heart is a Lonely Hunter, we perceive that Biff also has a strong desire to have children of his own; he wishes that Mick and his niece, Baby, were his own children.
Biff clearly has unresolved sexual anxieties, but their exact nature is never made clear. He keeps all the parts of his life compartmentalized—the past from the present, his life upstairs in his room from his life downstairs in the restaurant, and his marital relationship from his sexual life. At one point, we learn that Biff chivalrously beat up his sister-in-law's husband when he bragged about beating her; yet after Alice dies, Biff starts to sew and use his wife's perfume, expressing an unexpected feminine side to his personality. Neither Biff nor McCullers explains or integrates these conflicting impulses, which leaves us to assume that Biff himself is unable to resolve these inner conflicts.
Dr. Copeland is perhaps the most noble character in the entire story, as a black man who has made many personal sacrifices to devote his entire life's work to furthering the education and uplift of the black community. Dr. Copeland went to the North as a young man to get a college education, and then came back to the South to put his education to good use among the impoverished black community. He speaks very carefully and articulately, never once using the colloquial slang that characterizes the speech of the other black characters, such as his daughter, Portia, and his son Willie. Dr. Copeland feels a constant frustration with what he perceives as the ignorance of black people and their blind acceptance of an inferior societal position—a clear parallel to Jake Blount's frustration with the ignorance of lower-class workers. Dr. Copeland feels that education and strong teachers and leaders are the best means of combating black ignorance and poverty, but he is unable to find anyone of his own race who can help him with his goals. Dr. Copeland constantly feels alienated from both his own family and the broader black community, largely due to his radical views. Dr. Copeland's children have largely accepted the position white society has given them; all of them except Portia are afraid to even come to his house to visit because they know he will chastise them for the choices they have made in their lives.
Dr. Copeland, like Jake Blount, is a Marxist, but he does not have the same confused conception of the theory's implementation that Blount does. At the end of Part Two, when the two men finally discuss their political views, their personal, educational, and racial differences make it almost impossible for them to communicate; as a result, neither recognizes the other as a fellow reformer. Dr. Copeland's brand of Marxism is so highly intellectualized that he communicates his theory no more effectively than Jake does with his drunken rambling.
Jake is a wanderer who comes to town with confused and passionate plans for a socialist revolt. He drinks almost constantly for the first few weeks he is in town, spending almost all his time at Biff Brannon's New York Café. Once Jake meets Singer and decides that Singer, like him, "knows," he stays in town and gets a job at a local carnival. Of all the characters, Jake is the most prone to violent outbursts and genuine mental instability—his speech is never constant in tone, changing from intellectual to crass to boisterous to rage at a moment's notice. He is constantly consumed with his desire to see workers rise up in revolt; the only time he ceases to think about how to achieve his misguided socialist reforms is when he drinks himself into a stupor.
Jake is also the least sensitive of all of the characters, and he is no expert at personal interaction. All of the other main characters have other friends, acquaintances, or family outside of their relationship with Singer, but Jake confides in nobody else except the deaf-mute. After Singer dies, Jake is blindingly angry that he has spent so much time telling his dreams and plans to a man who is now dead. At the end of the novel, Jake leaves town to search for another person who will share his views and collaborate with him in his plans for violent revolt and revolution.