Matt Damon’s Oppenheimer role is as memorable as any in the celebrated historical epic. The cast of Oppenheimer is filled with some of the biggest heavyweight actors playing some of the most important people in recent American history. It’s a bit darkly humorous that it took an Englishman like Christopher Nolan to thoroughly examine one of the most defining moments of the United States. Dozens of real critical figures are accounted for in Oppenheimer, some for a scene, others as main characters.