His older brother is Takeshi Okamoto, a member of the Red Army Faction, which hijacked an airliner in March 1970 to North Korea.

[3] On May 30, 1972, Kōzō Okamoto along with Yasuyuki Yasuda, and Tsuyoshi Okudaira, landed at Israel's Lod Airport via Air France Flight 132 from Rome.

Upon retrieving their luggage, they took out automatic weapons packed inside the suitcases and opened fire on other passengers in the baggage claim area.

The idea behind the joint effort was for the JRA to carry out attacks for the PLFP, and vice versa, in order to reduce suspicion.

[9] On July 20, 1973, PFLP and JRA operatives hijacked Japan Air Lines Flight 404,[10] demanding Okamoto's release in exchange for the hostages on board; Israel refused to comply.

After his release from prison in Israel, Kōzō Okamoto moved to Libya, then Syria, and finally to Lebanon where he reunited with other members of the Japanese Red Army.

[11] On February 15, 1997, Lebanon detained five Red Army members, Haruo Wakō, Masao Adachi, Mariko Yamamoto, Kazuo Tohira and Okamoto for using forged passports and visa violations.

[15] On May 30, 2022, Okamoto appeared at a ceremony in Beirut marking the 50th anniversary of the attack, laying a wreath on the graves of his fellow JRA militants and posing for photos with PFLP supporters.