The exposition of the "Sonny's Blues" starts when the narrator introduces characters, scene, and situation of the story. The narrator learns from a newspaper that his younger brother, Sonny, has been arrested "for peddling and using heroin." (Baldwin 83) The narrator is a high school teacher, and his wife is Isabel. Leaving the school, the narrator comes across an old friend of Sonny's in the schoolyard. They talk about Sonny's arrest and tell each other some their fears. The friend says that he "can't much help old Sonny no more." This angers the narrator because it reminds him that he himself had give up trying to help his brother and not even seen Sonny in a year. However, he keeps in touch with Sonny again after his daughter dies. It is also the moment the narrator begins to wonder about Sonny again. The scene ends the exposition, and opens the story's rising action part.
The story continues as the narrator meets Sonny after Sonny get out of prison. As Sonny's request, they take a long cab ride and recall their memories that they had experienced in "vivid, killing streets" in their childhood. Next, we hear the conversation between the narrator and his mother about his father and the death of his father's brother. The mother's story makes the narrator realize how important he and his brother are to each other and how he, as the older, needs to let Sonny know "he is there" for Sonny. The narrator experiences a feeling of guilt, as he has not done as his mother asked, but he also remembers that Sonny's choice of being a jazz musician "seemed beneath him, some how." The conflict keeps rising as Sonny and the narrator argue about Sonny's choice to be a jazz musician while Sonny has not finished his high schools degree yet