Nathan Algren is a fictional character from the 2003 film The Last Samurai, portrayed by actor Tom Cruise. He is a former American Civil War officer who becomes a military advisor to the Japanese government during the Meiji Restoration. Algren struggles with his past and finds himself drawn to the samurai culture. Throughout the film, Algren learns about honor, loyalty, and the way of the samurai, particularly through his relationship with Katsumoto, a samurai leader played by Ken Watanabe. His journey reflects themes of redemption and cultural understanding as he navigates the clash between traditional and modern values in Japan.