Yoshio Kodama was the fifth son of an unsuccessful businessman in Nihonmatsu City, Japan. He was sent to Korea to be raised by relatives. In Korea, Kodama's upbringing was filled with isolation and child labor in industry. These experiences sensitized him to the needs of workers. He became first a socialist, then an nationalist member of Kenkoku-kai, a radical rightist group. Later he formed his own group, the Dokuritsu Seinen Sha (Independence Youth Society). By 1937, he had spent a total of six years in either a jail or prison cell.

Kodama used his rightist connections to enter the realm of foreign policy and eventually became a spy for the Japanese government during World War II. He not only gathered intelligence information but became a very wealthy man from operation Kodama Kikan (Agency). The Kikan gathered strategic materials for the war effort. By the end of the war, Kodama was a rear admiral in the Japanese Navy. In 1946, he was imprisoned in Sugamo Prison for nearly three years as a suspected war criminal. He was never formally charged.

Upon his release in December 1948 from Sugamo, Kodama strengthened his ties with the Japanese criminal underworld, the Yakuza, and with American intelligence agencies, most notably the CIA. Kodama unified the yakuza gangs and became a leader in Japanese politics in the Liberal Democratic Party. Through the 1960s and early 1970s, Kodama was powerful and wealthy.

Yoshio Kodama's fall from power mirrors that of American gangster Al Capone. In 1972, it was revealed that he has accepted $2.1 million in payoffs from Lockheed Corporation to influence its hold on the competitive Japanese market. In the wake of the Lockheed scandal, tax officials investigated his finances and arrested Kodama for tax evasion. Kodama was indicted for bribery, perjury and exchange law violations. He was never tried due to illness-related delays. He died from a stroke on January 17, 1984.