The American is a pretty surprising title, given that Christopher Newman tries to renounce his American identity in France. Based on the title alone, it sounds like Newman doesn't totally succeed in shaking off his red, white, and blue regalia.
Newman's stubborn American spirit leads to a bunch of the conflict in the book. Even when he thinks he's succeeded with Claire and her family, the Bellegardes call the engagement off—just because Newman wasn't born into an aristocratic French family.
What if the title was The Frenchman? Something tells us we'd get an entirely different kind of story.