We are mediated and instructed by the lawyer’s narration. So he is an unreliable narrator. But he is our eyes and ears of the world of the story. In that respect, he is the main character because we see the world through his eyes and his mind. But the story is not about him. In that respect, the main character is Bartleby. Without Bartleby, there is no story. You could choose either one. If we had insight into Bartleby’s mind or if we had an objective, omniscient narrator, it would be much easier to determine who the main character is.
In fact, since we get the entire story from the narration of the lawyer, we necessarily have to take him at his word. Does Bartleby really do all these things? If he does, how does the lawyer’s interpretation add or subtract from our understanding of Bartleby? The lawyer admits he is not ambitious and sort of goes with the flow of business and history. Bartleby represents the opposite, utilizing free will seemingly for the sake of free will itself. In this context, the narrator and Bartleby are reflections of two approaches to life: passivity and free will. In this context, the main character is “any” modern worker. To take it a step further in the psychological dimension, Mordecai Marcus suggests that Bartleby is the narrator’s psychological double. Like the book/film Fight Club, Bartleby is symbolic of the narrator’s underlying desire to escape the monotony of the modern working world. In this case, both are the main character because Bartleby is a manifestation of the lawyer’s psyche.