Motokuni first became the Shugo of Echizen Province where his father Yoshito had served as the Shugo; however, Motokuni gave up this post for a Shiba clan member as Echizen Province was originally their branch province, and he instead was granted by the Shiba clan the Shugo post for Ecchu Province.
当初は父の義深が守護職を務めていた越前国の守護職であったが、元々斯波氏の分国であったためこれを譲り、代わりに越中国の守護職を斯波氏から譲られている。