ichidan verb, transitive verb
serve out one's term; complete one's service
Used for fulfilling a fixed period of work, apprenticeship, or duty, often with a sense of perseverance until the end.
彼は五年間の見習い期間を勤め上げた。
He served out his five-year apprenticeship.
定年まで勤め上げる
I intend to work until retirement.