Content Warning: This section of the guide discusses extreme violence.

Tolly Driver is the protagonist and narrator of I Was a Teenage Slasher. Tolly is described as a lanky teen, which makes him an unlikely candidate for a killer. He also has an allergy to peanuts, which Amber uses against him during their final confrontation. Although he is a high school student, he occasionally works at his mother’s hardware store, helping to move goods around in the warehouse. The narrative is framed as a memoir that Tolly has written 17 years after the Lamesa killings. This allows Tolly to make asides about the ways the killings have affected his life, whether through public perception, his remorse, or the use of his abilities at work. When he admits to fictionalizing an encounter with a welder during his memoir, Tolly admits that his narration may be unreliable in parts. He produces the memoir for Amber, leaving it for her to find in the glove compartment of her retired truck.

When the narrative begins, Tolly is grieving the loss of his father, who worked as a pumper. Tolly believes that he is destined to follow the same path in life, an idea that is reinforced by his place in the social hierarchy of his high school.