O'Brien is the author and protagonist of If I Die in a Combat Zone. He is a serious, earnest man. Always able to see at least two sides to an issue, he is even-handed to a fault. He is against the war in Vietnam, and yet he hesitates to refuse to serve.

O'Brien grew up in a small town in Minnesota. As a boy, he was "too small for football" and "couldn't hit a baseball" (14). He turned to books and he read widely. In recounting the summer of 1968, after college and before he reports for the draft, O'Brien recalls debating the Vietnam War with his friends. During basic training and in Vietnam, O'Brien has few friends, and he sees himself as somehow set apart from the other soldiers. In basic training at Fort Lewis, he feels loathing for most of the other soldiers: "I did not like them, and there was no reason to like them […] I hated the trainees even more than their captors. I hated them all" (33).

The question of what courage is occupies O'Brien. He honestly recounts his moments of cowardice: lying on his back waiting for the shooting to stop, and not firing his rifle.