Frederick Winterbourne is a young American man, though older than Daisy Miller, who has spent a lot of time in Europe. He was educated in Geneva and is familiar with the social structures and customs in places like Vevey and Rome. Given his experience, he is well-equipped to navigate the social complexities of traveling abroad. The narrator vaguely hints that he has had liaisons with other women but does not give any details.

Though Winterbourne wants to appear to be judicious about Daisy’s behavior and frequently defends her or gives her the benefit of the doubt, he is still operating within the rules and boundaries prescribed by the wealthy class to which he belongs. Daisy’s behavior toward him, and other men, confuses him; for much of the novella he is not sure whether she is a respectable lady or not. He uses her behavior, and not her humanity, to judge whether she is worthy of his respect. When he sees Daisy with Mr. Giovanelli at the Colosseum late at night, he decides that she is not. He is often concerned with labels like “lady” and “gentleman,” and while he believes himself to be a gentleman, he condescendingly thinks that Giovanelli is “not a gentleman [.