He was very knowledgable about Yusoku kojitsu (court and samurai rules of ceremony and etiquette) and his diary titled "Nagaoki sukuneki" has been handed down up to date, although almost of his writings were lost in the Onin War.
有職故実に詳しく、日記『長興宿禰記』が今日まで伝わっているが、多くの文物は応仁の乱で失われた。