Tom Cruise portrays a United States Captain of the 7th Cavalry Regiment, whose personal and emotional conflicts bring him into contact with samurai warriors in the wake of the Meiji Restoration in 19th Century Japan. The film's plot was inspired by the 1877 Satsuma Rebellion led by Saigo Takamori, and the westernization of Japan by foreign powers, though in the film the United States is portrayed as the primary force behind the push for westernization. To a lesser extent it is also influenced by the stories of Jules Brunet, a French army captain who fought alongside Enomoto Takeaki in the earlier Boshin War and Frederick Townsend Ward, an American mercenary who helped Westernize the Chinese army by forming the Ever Victorious Army.

Can we conclude that was the last samurai based on a true story?
yes