Mutsu, was born as the son of Date Munehiros, a samurai and the trailer sonno Joi movement from Kishū. In the last days of the Tokugawa shogunate Mutsu was at the Kaientai, a shipping company and forerunner of the later Japanese Navy.
During the Meiji Restoration, he served as Governor of Hyogo, 1871 Kanagawa and other prefectures as well as a member of the Genrōin.
Because of his involvement in the Risshisha and conspiracy to overthrow the government, he was released and had to spend in jail four years and four months.
After his release, he visited Europe and the United States and entered into the Foreign Ministry after his return a. In 1888 he was Minister Plenipotentiary in the United States. Two years later he was elected to the Teikoku gikai.
Under Yamagata and Matsukata Masayoshi Aritomo he was Minister of Agriculture and Commerce, under Itō Hirobumi foreign minister.
After Otsu Cities incident Mutsu and Matsukata tried the most senior judge of the Supreme Court Kojima Korekata influence, the death penalty for Tsuda Sanzo to apply the assassin to appease Russia. This request was rejected by the majority of members of the Supreme Court.
In 1894 he signed the Anglo -Japanese trade and navigation treaty, which broke down the consular jurisdiction in Japan.
The Donghak uprising led to a deterioration of Sino- Japanese relations. Mutsu was an advocate of a hard line against China, leading to the First Sino-Japanese War.
1895 negotiated Mutsu during the intervention of Shimonoseki.
His grave is in the cemetery of Jufuku -ji.