In 1441, after his father, Yoshinori, was killed by Mitsusuke AKAMATSU in the Kakitsu War, his older brother by the same mother, Yoshikatsu ASHIKAGA, was installed as the Shogun.
嘉吉元年（1441年）、父の義教が嘉吉の乱で赤松満祐に殺された後、将軍職は同母兄の足利義勝が継いだ。