He was the adoptive heir of the 12th family head, Mochiyo OUCHI in 1441 to succeed the family head who controlled four provinces, Suo Province, Nagato Province, Chikuzen Province, and Buzen Province, because Mochiyo was involved in Kakitsu War and died.
第12代当主・大内持世の養嗣子となる、1441年、持世が嘉吉の乱に巻き込まれて死去したため、その後を継いで当主となり、周防国・長門国・筑前国・豊前国の四ヶ国を領する。