Tokikuni was born to the Yamashina branch family, but Akitoki YAMASHINA of the Yamashina head family died without his heir in 1462, so Tokiyuki became the adopted child and inherited the head family from Akitoki.
山科家の庶流に生まれるが、本家の山科顕言が寛正3年（1462年）、嗣子無きまま没したため養子となり、本家を相続。