Griffin Jennings is the protagonist and narrator of History Is All You Left Me. He has dark hair, a slim frame, and hazel eyes. Griffin weaves together two stories, one in the past tracing the arc of his relationship with Theo and one in the present as he copes with Theo’s sudden death. Throughout the novel, Griffin battles with his ongoing grief over Theo’s death, his guilt over lying to Theo about his relationship with Wade, and his resentment toward Theo for moving on with Jackson. Peppered into Griffin’s narration is information about his obsessive-compulsive disorder. Griffin caters to his compulsions throughout most of the novel, fearing the anxiety that comes with not appeasing them. Griffin’s main story arcs explore his breakup with Theo, Theo’s death, and his compulsions.

For most of the novel, Griffin grieves Theo. In the “History” chapters, Griffin tells the story of their romance and how he sabotaged it when he feared Theo would leave him first if they tried a long-distance relationship. Griffin begins mourning Theo the moment he learns that Theo wants to try for early admission. Despite trying to remain optimistic about their future, Griffin breaks up with Theo on Theo’s final day in New York.