Captain Nathan Algren
Algren is a veteran of the Civil War and of the Indian Wars, and he is both guilt ridden and scarred by witnessing the massacre of the Native Americans at Washita River. He is an alcoholic and cannot hold down a job which is why he accepts Colonel Begley's offer of a post training the Imperial Army.
He is captured during the first battle but the routing of his soldiers is not his fault; they are untrained peasants when he first starts to train them and he is very vocal about the fact they are not yet ready for battle. He fights to the death, which is why the Samurai leader, Katsumoto, decides to take him back to the village instead of killing him. He inspires a grudging respect from his opponents and they in turn earn his respect as wel.
Algren feels a strong tie to the Samurai very quickly and appreciates the culture and history of the country. He feels that it is important that the links to the past are maintained and not completely sacrificed to the future. It is surmised at the end of the film that he returns to the village to continue a relationship has has started with the widow of a Samurai he killed in the battle at the railroad.
Lord Katsumoto Moritsugu
Once upon a time, Katsumoto was Emperor Meiji's most trusted teacher. He is a Samurai, a warrior, a poet and a philosopher. He becomes disillusioned with the young Emperor when he takes too much notice of the wishes of Omura, whom Katsumoto despises. He decides to organize a revolt against the new imperial Army and the progressive measures they are forcing on the country.
Katsumoto is a courageous and honorable man and respects Algren because he sees these qualities in him as well. He is prepared to fight to the death and sees more glory in death than in capture or surrender. Although he dies as a result of the suicide mission at the end of the film, he still manages to influence the Emperor because his willingness to die for the honor, history and tradition of his country eventually inspire Meiji to abandon the trade deal and to sever ties with Omura.
Colonel Bagley
Bagley was once Algren's commanding officer in the 7th Cavalry Regiment. He played a significant role in the slaughter of Native American civilians at the Washita River massacre and it is this that Algren cannot forgive him for. Bagley is killed by Algren in their final battle after Algren plunges his sword into his chest.
Mr Omura
Industrialist, progressive politician and all around nefarious character, Mr Omura is a rich and successful businessman who quickly learns how to manipulate the young, naive Emperor. He is wholeheartedly in favor of Westernization and feels that the old traditions of the Samurai should be left firmly in the past. He hates the nobility, and therefore the Samurai, because he feels that his family were among those who were oppressed during Samurai rule. He is in truth in favor of anything that creates more power for himself, and less interested in the morality or ethics of any of the agreements or machinations in which he has a hand.
Emperor Meiji
Meiji is keen to modernize Japan and believes that Westernization is the most effective method of doing this. He believes this can only strengthen Japan whom he fears is going to lag behind other nations in terms of progress. He is young, naive and inexperienced when he takes power and therefore used by Omura without having any knowledge of this. He is maleaable of thought and easily influenced.
Simon Graham
Graham is a British interpreter who is also considered an expert in Samurai history. He is practical and has no Samurai soul whatsoever, although he does come to understand the way of the Samurai and to have a great respect for Katsumoto. He and Algren have a friendly relationship and it is he who suggests that Algren has returned to the village to spend his life with Taka.
Zebulon Gant
Algren's close friend Gant travels with him to Tokyo to take on the job of training the Imperial Army. He is loyal and also talks him into taking the job in the first place, hoping that it will in part start to turn his life around for the better. He is killed in the opening battle at the railroad by Samurai Hirotaro, Taka's husband whom Algren kills in anger and grief.
Taka
The widow of the Samurai killed by Algren, Taka is also Katsumoto's sister. Although the language gap renders their relationship somewhat speechless to begin with, Taka and Algre develop a deep love for each other that it is believed Algren returns to after his meeting with the Emperor at the end of the movie.
