Kathleen is Tim O’Brien’s daughter, who is a young child when Tim is middle-aged and writing short stories about his experience in Vietnam. Kathleen is both curious about her father’s time as a soldier and is also puzzled by how much it weighs on his mind. As a child, she can’t comprehend the depth of her father’s trauma or Vietnam’s heavy, polarized connotation in the greater American consciousness. Her childhood innocence stands in stark contrast to the difficult and horrifying content of the book, providing a respite in the simplicity of childhood. However, Kathleen’s innocence and naivety also reflect the innocence and naivety of Tim and his fellow young soldiers, who arrive in Vietnam as boys and are quickly changed and damaged by their experiences. Even as a middle-aged man, Tim still feels that his experience in Vietnam, and his subsequent feelings about those experiences, are as unclear and confusing to him even now as they are to his ten-year-old daughter.

Thus, Tim often uses Kathleen as a mouthpiece through which he can ask himself questions about Vietnam that are seemingly simple, but still haunt him decades later. For example, when Kathleen asks him if he’s killed someone or why he still spends so much time thinking about Vietnam when it happened so long ago, the questions on the surface are easy to answer, coming from the mind of a naive child. But when Tim dives further into those questions, he finds that Kathleen is probing the core of his inner conflicts.