A Choshu domain samurai from Hagi, Nagato Province (present-day Yamaguchi Prefecture). He rose to prominence in the military and political world as a trusted aide to Yamagata Aritomo. After the First Sino-Japanese and Russo-Japanese Wars, he served as the 11th, 13th, and 15th Prime Minister, forming the "Katsura-Saionji Era" in which he and Saionji Kinmochi alternated in power. His total days as prime minister reached 2,886, the longest consecutive record of the time (still second all-time). He worked to conclude the Anglo-Japanese Alliance (1902) and as wartime prime minister led Japan to victory in the Russo-Japanese War (1904-1905). He conducted diplomatic negotiations including the Katsura-Harriman memorandum and Taft-Katsura agreement that contributed to Japan's elevated international standing after the Portsmouth Treaty. In late 1912, when the Third Katsura Cabinet was formed, a fierce opposition movement called the "Movement to Protect Constitutional Government (Taisho Political Crisis)" broke out; Katsura attempted to form a political party (the Rikken Doshikai) but died in office in 1913 due to illness. He died at 65. As the offspring of clique and military politics nurtured by Yamagata Aritomo, he was a politician who stood at a turning point of the era amid the tide of Taisho Democracy.

A pragmatic politician moving by the logic of clique and military politics as Yamagata Aritomo's trusted aide. Despite his army background, he possessed diplomatic realism and left achievements in international diplomatic negotiations. Known as a politician also skilled in political maneuvering.

His total days as prime minister remain the all-time second longest. The diplomatic achievements after the Anglo-Japanese Alliance and Portsmouth Treaty raised Japan's international standing. The "Katsura-Saionji Era" is recorded in Japanese political history as a symbol of political stability from the end of Meiji through the beginning of Taisho.