In 1570, after his father Nobunaga attacked Kitabatake, Nobukatsu became the adopted heir to Tomofusa KITABATAKE in return for reconciliation, and married a daughter of Tomonori KITABATAKE.
元亀元年（1570年）、父・信長の北畠攻めの際に和睦の条件として、北畠具房の養嗣子となり、北畠具教の娘を娶る。