Yukinaga Konishi was born in Higo Province, Kyushu, territory of the Sagara clan. Yukinaga joined the Toyotomi Army as a young man, serving in the Battle of Komaki-Nagakute under Hideyoshi Hashiba. He also served in the Conquest of Kyushu along with Kiyomasa Kato and Mitsunari Ishida in 1587. In 1592, he was given command of the Japanese army that invaded Joseon Korea during the Imjin War, and he seized Busan and Seoul before defending Pyongyang from the Koreans. Along with Kiyomasa, he defended Suncheon Castle from the armies of both Joseon and Ming. After the death of Hideyoshi, Yukinaga became a commander in Mitsunari's Western Army, Toyotomi loyalists who sought to resist the pro-Ieyasu Tokugawa Eastern Army, which drew supporters from territories loyal to Hideyoshi's conquered territories, while the Western Army drew supporters from Toyotomi Rebels. Yukinaga was one of the Toyotomi generals at the 1600 Battle of Sekigahara against the Tokugawa clan, and after the defeat, he fled to Mount Ibuki. However, Shigekado Takenaka captured him and had him executed when he refused to commit seppuku.