In the case of the succession dispute in Hosokawa clan, Nagayuki supported Sumimoto HOSOKAWA, who was a child of Awa shugo Hosokawa clan and later adopted by kanrei Masamoto HOSOKAWA.
細川氏の家督をめぐる内紛では阿波守護の細川氏の子で管領細川政元の養子となった細川澄元を支えた。