Ooomi was appointed personally by Ookimi for the reign: For the reigns from Emperor Hanzei to Emperor Anko during the middle of the 5th century, KATSURAGI no Tsubura was appointed Ooomi; for the reigns from Emperor Yuryaku to Emperor Ninken during the latter half of the 5th century, HEGURI no Matori was appointed Ooomi; for the reign of Emperor Keitai during the first half of the 6th century, KOSE no Ohito was appointed Ooomi; and for the reigns of Emperor Bidatsu to Emperor Suiko from the latter half of the 6th century to the early 7th century, SOGA no Umako was appointed Ooomi.
大臣は、各大王の治世ごとに親任され、反正天皇から安康天皇までの治世に当たる5世紀中期には葛城円が、雄略天皇から仁賢天皇までの治世に当たる5世紀後期には平群真鳥が、継体天皇の治世に当たる6世紀前期には巨勢男人が、敏達天皇から推古天皇までの治世に当たる6世紀後期から7世紀初期には蘇我馬子が、それぞれ大臣に任命された。