The Narrator, true to form, narrates the events that transpire in Trapped in the Closet. The Narrator is a Greek Chorus-type character who never interacts with any of the other characters, save for a scene in chapter 14 when Roxanne accidentally knocks a cigar out of his mouth.
He is always shown wearing an expensive suit, much like many other characters.
In the first eight chapters Sylvester was the narrator, and did so in the first person; however, as the focus shifted away from Sylvester onto other characters, The Narrator comes out of nowhere and starts narrating in the third person. This is never more evident than in Chapter 11, in which the narration switches between first and third person at random intervals until finally settling on the latter. Curiously, in Chapter 1, Sylvester/The Narrator refers to Gwendolyn, Sylvester's wife, in the second person, but uses third person in the chapters when she actually does appear.
In the first 22 chapters, The Narrator narrates from the exact location at which the action is taking place. However, from Chapter 23 onward, he narrates from inside of an apartment decorated with many books, a telescope, a constellation map, a gun in a wooden case, and a framed newspaper headline with Joey and Beeno's mugshots on it (the headline reading "Chicago Mob War Erupts.")