Much like many of Capote's young male characters, Joel Harrison Knox is essentially an orphan. He feels disconnected from his peers due to his delicate, almost feminine appearance, which leads him to relate to Little Kay from "The Snow Queen." Joel wonders if he's been transported to a cold palace, as his life seems lacking in emotional warmth. He finds comfort only when he shares his lunch with a Black stevedore or is selected by Mr. Mystery to participate in a magic show. After his mother's death, Joel is taken in by his aunt, Ellen Kendall, yet he continues to feel like an outsider in her household.

Despite the family's kindness, Joel harbors resentment and often behaves unkindly, particularly towards his deaf cousin, Louise. When his father, Ed Samson, invites him to live at Skully's Landing, Joel innocently anticipates meeting the charming figure he has imagined. However, throughout much of the story, Joel feels alienated at Skully's Landing, writing numerous letters to Ellen, begging for rescue from his new "family": a paralyzed father, an eccentric stepmother, and her drag queen cousin, Randolph. It is only after a botched escape attempt leaves him gravely ill, and Randolph nurses him back to health, that Joel begins to realize he has become an integral part of life at Skully's Landing.

In Other Voices, Other Rooms, the main theme revolves around the journey into adulthood. When Joel departs from New Orleans for Skully's Landing, he is still very much a child. By the end of the novel, he recognizes his personal development and views his past self with a sense of detachment. He comes to terms with his sexual attraction to Randolph. Moreover, Joel realizes that he has a stronger character and is the only one who can provide Randolph with the assurance that everything will be alright. Their trip to the Cloud Hotel reveals Randolph's utter helplessness, but upon returning, Joel also comes to understand that he remains isolated—not only from his "bloodkin," but also from the outcasts who have been his only companions.

Much like Joel and Randolph, the majority of characters in the novel lack a sense of security. Often, in their frantic efforts to flee perceived threats, they encounter genuine dangers that are much more severe. For example, Missouri Fever wants to leave Skully's Landing before Keg Brown is released from prison and returns to harm her. After gaining her freedom through her grandfather's death, she sets out for Washington, only to be gang-raped, which forces her to return to Skully's Landing. Similarly, Idabel Thompkins escapes from her father and sister, fearing they will suppress her individuality, only to fall under the influence of Miss Wisteria, the carnival midget, who appears to have inappropriate intentions toward her.

Throughout the novel, Capote explores the interconnected themes of death and transformation. In each of the three sections, a death significantly reshapes Joel's life. In Part One, the death of Joel's mother compels him to leave his familiar family environment and move in with his father. He embarks on a solitary journey from New Orleans to Skully's Landing, only to find himself in a household burdened by both physical and psychological weaknesses. Here, he must navigate the boundaries between reality and illusion, all while feeling completely alone and vulnerable.

In Part Two, the death of Jesus Fever occurs. Joel had perceived Jesus as almost immortal due to his old age, but the old man's death highlights the theme of change. Furthermore, with Missouri no longer needing to care for her grandfather, she leaves Skully's Landing, leaving Joel with a sense of having...