He was born Miyagawa Katsugoro on a farm in Musashi Province. His father tilled the soil. There was nothing in his origins that suggested the life he would carve out — nothing except the boy himself.

At fourteen, in 1848, he began training at the Shieikan dojo under master Kondo Shusuke, learning the Tennen Rishin-ryū (天然理心流, Tennen Rishin-ryū) school of swordsmanship. He was exceptional enough that Shusuke adopted him — gave him the Kondo name, the dojo's lineage, and a place in the samurai class he had not been born into. By 1861 he was the school's fourth-generation master. By 1863, commanding the Shinsengumi (新選組, Shinsengumi) in Kyoto, he was one of the most feared men in Japan.

The Shinsengumi served the Tokugawa shogunate as a roving police force in the imperial capital, tasked with hunting down anti-shogunate loyalists. They did their work without restraint. In July 1864, Kondo's men burst into the Ikedaya Inn at night, swords already drawn, and cut down a gathering of rōshi (浪士, rōshi) — masterless samurai — who had been plotting to burn Kyoto and kidnap the Emperor. The raid made the Shinsengumi's reputation: ruthless, effective, loyal to the old order beyond question.

But the old order was already dying. By late 1867, Emperor Meiji's supporters had formally ended the shogunate. The Boshin War (戊辰戦争, Boshin Sensō) — the civil conflict between the new Imperial government and Tokugawa loyalists — had swung decisively against the side Kondo had spent his life defending. The Shinsengumi fought rearguard actions, retreating northeast through the winter. Kondo, wounded, commanding a shrinking force, moved with his men to Nagareyama in Shimosa Province.

Somewhere in that retreat he stopped using his name. He called himself Okubo Yamato — a provincial alias thin enough that anyone who had seen him before would see through it. In early April 1868, as Imperial forces pushed toward Edo, a Satsuma officer named Arima Tota saw through it immediately. He suspected the man drilling soldiers at Nagareyama was Kondo Isami, and ordered him seized.

The arrest had its own irony. Kondo had spent years arresting men — men who had been hiding under false names, men whose friends had given them away, men seized in the night and transferred to face judgment. Now it was his turn. He was moved to Itabashi. Put on trial April 30. Found guilty. Sentenced to death.

He asked to die by seppuku (切腹, seppuku) — the ritual disembowelment reserved for samurai, the death that acknowledged a warrior's honor even in defeat. The request was denied. His birth record showed he was the son of a farmer. Whatever he had made of himself through talent and adoption, whatever name he had earned, the new Meiji government judged that he was not entitled to the warrior's ending. On May 17, 1868, the executioner Yokokura Kisoji beheaded him at the Itabashi execution grounds. According to some accounts, his severed head was sent to Kyoto to be displayed.

His deputy, Hijikata Toshizo (土方歳三, Hijikata Toshizō), refused to accept the terms Kondo never lived to negotiate. He gathered the Shinsengumi's survivors and fled north, fighting through the summer and into 1869, until the last Tokugawa holdouts made their stand at Hakodate in Hokkaido. Hijikata died there on June 20, 1869 — in battle, sword in hand, the death his commander had been denied.

The story of Kondo Isami might have ended there, a footnote in the defeat of the Tokugawa. Instead it grew. In death he became everything he had never quite been allowed to be in life. The Shinsengumi became the subject of novels, films, television dramas, anime — one of the most romanticized forces in Japanese popular culture. The farmer's son who had clawed his way into the samurai class, who had enforced an old order with steel and nerve, who died with a commoner's death sentence and a warrior's reputation — that combination proved irresistible to every subsequent generation.

The name he had been given, not born with, turned out to be the one that lasted.