[4] Manibusan graduated from California State University at Fullerton with a Bachelor of Arts degree in Criminal Law in 1977.

[2] In 1986, Governor Pedro Pangelinan Tenorio appointed Manibusan, the Director of the Department of Public Safety.

Prior to the election he also held an honorary appointment as the Civilian Aide to the United States Secretary of the Army for the CNMI.

[14] Manibusan succeeded Gilbert Birnbrich, who was appointed by Governor Eloy Inos five months before the election.

[15] In 2022, Manibusan defeated former judge Juan Tudela Lizama by approximately ten points to be reelected Attorney General.