Myboto was born at Omoï, Moanda, located in southeastern Gabon, in 1938. He became a member of the PDG when it was founded in 1968, and he was Director of the Cabinet of the Minister of Water and Forests from September 1968 to May 1971. He joined the PDG Political Bureau at the party's Constitutive Congress in September 1970. After working as Secretary-General of the Gabonese Marble Company ("Société Gabonaise de Marbrerie", SOGAMAR) from May 1971 to November 1972, he became the PDG's Administrative Secretary in November 1972.