In 1860, seventeen-year-old samurai Tateishi Onojirō, nicknamed "Tommy," made headlines across America for his real and imagined adventures as part of the 1860 Japanese Embassy, the first Japanese diplomatic mission to the United States. The perception of Tateishi's interracial romantic encounters with American women opened up to controversy and questioning the hierarchies of race and culture fundamental to many antebellum American concepts of civilization. This book reveals how Tateishi and his fellow samurai diplomats sparked a whirlwind of national optimism and cultural fantasy within the United States that challenged linked conceptions of race, masculinity, and power. After returning to Japan, Tateishi fought in Japan's civil war and contributed to many of the defining cultural and national endeavors of nineteenth-century Japan. This book reveals the influence of samurai on antebellum American identity formation and the incredible life of a samurai celebrity and civil war survivor.