He was born in Kyoto, the fourth son of the court noble Sanjō Sanetsumu. His childhood name was Fukumaro. As a fourth son, he was at first to be adopted into a branch family. Known from childhood for his intelligence, he was taught strong reverence for the emperor by his Confucian tutor Tomita Oribe. This teaching would shape the course of his life.
His elder brother, the heir, died young. The brother's son should have succeeded, but the nephew was still small, and on Tomita Oribe's strong recommendation Fukumaro was named heir to the Sanjō house. That same year he came of age and took the name Sanetomi. A story tells that as a boy he used the rising-sun mark as his banner in war games, calling it the sign of the nation.
His father Sanetsumu had worked to issue an imperial order criticizing the shogunate in order to advance expulsion of foreigners. Therefore in the Ansei Purge the shogunate blamed him, ordering him into retirement, and many of the family's retainers including Tomita Oribe were arrested. In these painful circumstances Sanetomi formally succeeded to the Sanjō house. A strong resentment toward the shogunate was etched into his heart.
When Shimazu Hisamitsu came to Kyoto and the court grew active, Sanetomi was appointed to a post handling affairs of state and drew near the court's center. At first he favored cooperation between court and shogunate, but frustrated with a shogunate that would not move toward expulsion, he deepened ties with sonnō jōi activists of Chōshū and Tosa's Takechi Hanpeita.
As leader of the sonnō jōi court nobles he held great power, said to be such that even the regent could not oppose him. He received Shogun Tokugawa Iemochi in Kyoto and pressed him hard to promise expulsion. That year his friend Anegakōji Kintomo, a fellow noble of the same camp, was attacked and killed near the palace, deeply shocking Sanetomi.
Plans advanced for the emperor himself to lead expulsion, but in the coup of 18th day of 8th month Satsuma and Aizu sealed the palace gates and shut the sonnō jōi nobles out of the court. Sanetomi and six other nobles fled Kyoto for Chōshū, an event called the flight of the seven nobles. On the unaccustomed journey on foot, his feet are said to have bled.
In Chōshū he held repeated talks with Takasugi Shinsaku and others, and moved to Yuda near Yamaguchi, living in a detached house built at the family home of Inoue Monta. But Chōshū was defeated at the Kinmon Incident and, facing a shogunal punitive expedition and attacks by foreign fleets, was pushed into a painful position. Sanetomi and the others resolved to share Chōshū's fate.
The nobles, now five, crossed to Kyushu and were moved to Dazaifu. They were placed in the custody of the Fukuoka domain, with Satsuma and others paying their costs. The next year the shogunate tried to move the five to Osaka, but Sanetomi and the others resolved not to move even at the cost of their lives, and with Satsuma and others firmly opposed, the shogunate could not act.
When Tokugawa Yoshinobu returned power to the court, the five were pardoned and restored to their ranks. The next day the proclamation of imperial restoration was issued and a new government was born. On hearing the news, Sanetomi left Kyushu and returned to Kyoto to take a heavy post in the new government. His long years of exile had at last ended.
In the Boshin War he went to the Kantō and backed moves to defeat former shogunate forces in Edo. In the new government he became Minister of the Right and handled the governance of eastern Japan from Edo, renamed Tokyo. He reportedly said that as long as Tokyo was not lost, the realm would not be lost, keenly aware of eastern Japan's weight.
As Minister of the Right he read out the proclamation of the abolition of domains before the domain governors in Tokyo. That same year he became Grand Minister, standing at the top of government. When the Iwakura Mission left for the West, he headed the government that stayed in Japan and dealt with many difficult issues. His role was largely that of a mediator.
Fierce conflict arose within the government over whether to send Saigō Takamori as envoy to Korea, the Seikanron dispute. Sanetomi opposed it, fearing Saigō would be killed, but was caught between strong demands. Exhausted in mind and body, he collapsed complaining of chest pain, and in this political crisis of 1873 the government split deeply.
When the old council system was abolished and the cabinet system began, Itō Hirobumi became the first prime minister, and Sanetomi moved to the court as Lord Keeper of the Privy Seal, supporting the emperor. Often seen as an honorary post, it was an important role assisting the emperor. Sanetomi took on the role of mediating between Satsuma and Chōshū and calmed disorder in government.
At the ceremony promulgating the Meiji Constitution, he stood beside the emperor and presented the text of the constitution to him. That same year, when treaty revision talks stalled and the Kuroda cabinet resigned, he briefly also served as prime minister while remaining Lord Keeper of the Privy Seal. He was given the highest seat among subjects and treated as the foremost meritorious statesman.
He died after catching influenza. The day before his death, Emperor Meiji visited him in person and conferred the highest court rank. His funeral was held as a state funeral, and people across the country held memorials of their own accord. The funeral day was clear and warm, and the emperor is said to have called such weather Sanjō weather.
Shimazu HisamitsuSaigō TakamoriTokugawa YoshinobuTakasugi ShinsakuItō HirobumiTakechi Hanpeita (Zuizan)
Godai TomoatsuInoue KaoruItagaki TaisukeTani TatekiŌkuma ShigenobuYamagata AritomoEdward S. MorseGoto Shojiro
People of the Meiji period ・ People by period
Based on facts found in textbooks and biographies. Uncertain points are marked as such.