In 1869 he went to Tokyo to study French military methods and later entered the foreign language school in Yokohama. In 1870 he went abroad, studying military affairs and French in Paris, and returned to Japan in 1873.
He served in the domain military organization called the Kiheitai organized by Takasugi Shinsaku, seeing action in the shogunate expedition against ChoshQ and the Boshin civil war.
In 1875 he was appointed military attaché to the Japanese legation in Germany. In 1883 he accompanied War Minister Ôyama Iwao on a tour of various European countries for the purpose of inspecting military installations. As a result of the trip, the German military expert Klemens Wilhelm Jakob Meckel was invited to Japan to teach at the Military Staff College.
In 1885 Katsura advanced to the rank of major-general, and in 1886 became vice-minister of war.
In 1890 he advanced to the rank of lieutenant general. The same year, as a member of the budget drafting committee, he succeeded in winning passage for the budget submitted to the newly created Diet by the War Ministry in spite of opposition from the popular parties, gaining recognition of his political skill in the process.
In 1894 he served in the Sino-Japanese War alongside General Yamagata, commanding the Third Division and winning renown for his exploits. In 1895 he became governor-general of Taiwan. In 1898 he became war min-ister in the third Ito Hirobumi cabinet and continued to hold that post until the fourth Ito cabinet of 1900. In 1900 he dispatched troops to Peking to combat the Boxers and relieve the foreign legations that were under siege. At the same time he pressed for military expansion and adopted a conciliatory attitude toward the political parties.
In 1901 he formed the first Katsura cabinet, and though he was criticized for tlie inferior quality of the men who made it up, he succeeded in concluding the Anglo-Japanese alliance of 1902 and handling the problems that arose in Manchuria. He acted as prime minister throughout the Russo-Japanese War, which broke out in 1904, but resigned after the Hibiya riots that broke out in Tokyo in 1905 in protest to the Portsmouth Treaty that brought the war to a dose. Around this time, it became increasingly clear that Japan had designs to take over Korea.
In 1908 Katsura once more became prime minister and formed his second cabinet, and in 1910 he carried out the formal annexation of Korea. He also took steps to suppress the socialist movement, as seen in the arrests carried out in connection with the so-called lesc-majeste affair of 1910. In 1912, when pressure from the military brought about the downfall of the second Saionji cabinet, Katsura, while continuing to hold the post of home minister and head of the Board of Chamberlains, formed his third cabinet. But his attempts to form a political party of his own failed, and he faced attacks both from the older cliques in the government and the other political parties, who launched a large-scale popular movement known as the First National Movement to Protect the Constitution. As a result his cabinet fell in 1913, and he died the same year in a state of despondency.