To the narrator, jazz music is entwined with an image of Sonny that is wrapped up in drugs and making poor decisions. Just after their mother's death, Sonny confides in his brother that he really wants to become a musician. The narrator realizes that in his mind, he puts "jazz musicians in a class with what Daddy called 'good time people.'" He therefore refuses to listen to his brother's wishes, and when Sonny comes to stay with him later in the story, he asks his brother about the tendencies to wrap music and drugs into the same existence. He notes that Sonny's friends "seem to shake themselves to pieces pretty ... fast." Jazz music divides the brothers, as the narrator is unwilling to see the value it has in Sonny's life.

For Sonny, music represents freedom and passion. He is talented, and he actually first wanted to use music to leave Harlem after he foresaw the drug-laden path awaiting him there. Since his brother is unwilling to accept this possibility, Sonny temporarily gives up on his dream and follows the path toward a life filled with drugs. But he never really gives up on music. In those final scenes when he and his brother watch the tambourine lady, Sonny explains,

When she was singing before, her voice reminded me for a minute of what heroin feels like sometimes—when it's in your veins. It makes you feel sort of warm and cool at the same time. And distant. And—and sure.

Sonny's soul craves music, and creating it touches something inside him that fulfills his sense of purpose.

In the end, music serves as the bridge between the brothers. When the narrator finally chooses to really hear Sonny's music, he finally truly hears the voice of his baby brother. He sees Sonny's talents for the magic they truly are, and he begins to hear the story that binds the brothers together.

The song tells of both suffering and triumph, but both pieces of the song deserve to be told and heard. The narrator realizes as he listens to his brother's music that "freedom lurked around [them]" and that the two of them could finally "cease lamenting." Music opens the narrator to accept his brother not for what he has always wanted Sonny to be—but for the brother he has actually been given.

In James Baldwin's "Sonny's Blues," music is the central focus of Sonny's life—it is the only thing that seems to release him from his suffering: his addiction, growing up black, feeling alone and cut off from others, and a feeling that he has no one to love or understand him.

Baldwin believed in the power of art to save people from suffering, or at least to minimize their suffering.

It is not surprising that Baldwin gives Sonny's character the ability to play jazz—the blues—to better deal with his own suffering, including the awareness that he and his brother cannot communicate and therefore have no connection.

Sonny tries to verbalize to his brother just how important music is to him:

"Sometimes you'll do anything to play, even cut your mother's throat." He laughed and looked at me. "Or your brother's." Then he sobered. "Or your own."

The difficulty is that Sonny wants to make his living in a non-traditional way, one that his brother does not understand. The narrator knows nothing about jazz: he believes it is simply men sitting and fooling around with music. The narrator cannot see that it is so much more to the serious musician—and to Sonny, who has music in his soul. The narrator has been charged by his mother to care for Sonny, but he doesn't know how—certainly not in a way that will help Sonny.

Ironically, the music that Sonny's brother knows nothing about ultimately creates a bridge between the two men. And while the narrator may not completely understand jazz or the blues, while he may not know anything about the big names of this movement in music, he suddenly is able to better know his brother by seeing his connection to song.

...Sonny played. Every now and again one of them seemed to say, amen. Sonny's fingers filled the air with life, his life. But that life contained so many others... Then he began to make it his...it was no longer a lament...Freedom lurked around us and I understood, at last, that he could help us to be free if we would listen, that he would never be free until we did.

Not only does the music help the narrator better know his brother, but the blues bring to him the sources of his own suffering:

I saw my mother's face again, and felt, for the first time, how the stones of the road she had walked on must have bruised her feet. I saw the moonlit road where my father's brother died. And it brought something else back to me, and carried me past it, I saw my little girl again and felt Isabel's tears again, and I felt my own tears begin to rise.

Perhaps in losing his daughter, the narrator could never quite understand Sonny's suffering because it was different than his own; but Sonny's music illuminates the truth of suffering—a common feeling for a different reason. He understand life better, and death; and most certainly, he sees what a miracle music is to Sonny, and even how much it matters in his own life.