Negotiating the Treaty of Portsmouth - from left to right: the Russians at far side of table are Korostovetz, Navohoff, Witte, Rosen, Plancoff; and the Japanese at near side of table are Adachi, Ochiai, Komura, Takahira, Satō. The large conference table is today preserved at the Museum Meiji Mura in Inuyama, Aichi Prefecture, Japan.
Kogoro Takahira studied at the clan school. He graduated from Tokyo Imperial University.
In 1876, he joined the Ministry of Foreign Affairs. His first posting to the United States in 1879 was as an attaché and he was promoted to secretary in 1881. During a return to Asia, he served briefly as chargé d'affaires in Korea and as Consul General in Shanghai, China. In 1887, he returned to the United States as Consul General in New York City. Postings in Europe as Minister-Resident to Netherlands and Denmark, and as Minister Plenipotentiary at Rome, Vienna and Bern spanned the years before his 1901 return to Washington, D.C. He then continued as Japan's minister in the United States from 1901 through 1905.
Takahira participated in a number of important Japanese-US negotiations. Takahira was one of the principals of the Japanese delegation negotiating with the Russians to conclude The Treaty of Portsmouth, which ended the Russo-Japanese War.
In 1907, Takahira was named Ambassador to Rome. The Foreign Ministry called him back to Washington, D.C. in 1908-1909. As principal negotiator for Japan, his name is commemorated in the 1908 Root-Takahira Agreement, which was intended to ease Japanese-US tension by defining each nation's role in the Pacific arena and China.
Takahira later elevated to danshaku (baron) under the kazoku peerage system, and was appointed to the House of Peers, and subsequently served on the Privy Council.