Yoshida's birth father, Takeuchi Tsuna, was a samurai noble, and his mother was his mistress, possibly a geisha. He was adopted as a baby or small child by his father's friend, Yoshida Kenzo, also a samurai noble, and his wife. His adoptive father died in 1887, leaving Yoshida a wealthy but lonely boy.
He was educated for the diplomatic service and married into the emperor's circle of advisors. From 1907 to 1938 he was in Japan's diplomatic corps.
He was called out of retirement in 1945 to become foreign minister, and from 1946 to 1954 he had several terms as prime minister, during which he guided Japan through its post-war reconstruction and occupation to stable independence and economic regeneration.