At the same time, in accordance with the custom of being granted the right to use a portion of the superior's real name, he borrowed one of the characters from Yoshikatsu ASHIKAGA, who was the seventh shogun of the Ashikaga shogunate, and thus called himself Katsumoto; and supported by the guardianship of his uncle, Mochikata HOSOKAWA, he became the shugo-shiki (the rank of military governor) of the provinces of Settsu, Tanba, Sanuki and Tosa.
このとき第7代将軍・足利義勝から諱偏諱授与の風習を受けて勝元と名乗り、叔父の細川持賢に後見されて摂津国、丹波国、讃岐国、土佐国の守護職となった。