In 1635, he was promoted to Juichii (Junior First Rank) and, in June 1640, through reporting by Iemitsu, he was appointed to udaijin (minister of the right) that was quite exceptional for the Sanjonishi family.
寛永12年（1635年）従一位に進み、同17年（1640年）6月には徳川家光の執奏により、三条西家としては異例の右大臣に任ぜられる。