Terashima was born to a samurai family in Satsuma Domain (in what is now part of Akune, Kagoshima Prefecture).In 1862, he was chosen as a member of the group of students selected by the Tokugawa bakufu to study at the University College London in Great Britain.In 1873, he was appointed foreign minister, and negotiated the Treaty of Saint Petersburg (1875), which fixed the national boundaries between Japan and the Russian Empire.His efforts to re-negotiate the unequal treaties with the United States failed at the last minute due to British opposition.As Governor of Kanagawa Prefecture, he was responsible for connecting Tokyo and Yokohama by telegraph in 1868.