Bill O'Reilly appears in Transformers: Dark of the Moon as a fictionalized version of himself, the real-life news pundit known for hosting a television commentary program. In the context of the film, he is presented as a television interviewer with a confrontational style. His role is a brief but notable cameo, where he is seen conducting an interview.

The central scene featuring O'Reilly takes place on his television program. He interviews former Sector 7 agent Seymour Simmons, who is promoting a tell-all book about his experiences with the alien robots. O'Reilly's line of questioning is aggressive and takes a critical stance, suggesting that humanity should end its support for the Autobots, the heroic Transformer faction. This line of questioning reveals his character's primary motivation within the story: to challenge the official narrative and advocate for a skeptical, human-first position regarding the Autobots' presence on Earth.

O'Reilly's personality is defined by his trademark combative and dismissive demeanor. When Simmons reacts poorly to the interrogation and abruptly ends the interview, O'Reilly remains in control of the situation. He famously responds by calling Simmons a "pinhead," a signature insult associated with his real-life public persona, and concludes the segment by declaring, "Damage control". This interaction defines his key relationship in the film, which is an adversarial one with Seymour Simmons. The interview ends in a public confrontation, with Simmons storming off, making their dynamic tense and short-lived.

The character does not undergo any significant development or change, as his appearance is limited to a single scene. His notable ability, within the context of the film, is his effective use of his media platform to challenge and unsettle his guests, leveraging a confrontational interview style to provoke reactions. He serves as a minor character who adds a layer of real-world media skepticism to the film's fictional conflict between humans and alien robots.