As his father was a trustworthy retainer of the Emperor Gosaga, Tadakata became Ushoben (Minor Controller of the Right) at the age of 18, and in 1268 after his father's death, he was promoted to Sangi (councilor) and served the Retired Emperor Gosaga as denso (job title to relay massages of court's people to Emperor).
父が後嵯峨天皇の腹心であった事から、18歳で右少弁となり父の死後である文永5年（1268年）には参議に昇って後嵯峨上皇の伝奏を務める。