His nanny was Jotoku-In, daughter of Takigawa Kazumasu (滝川一益), who was one of the senior vassals of Oda Nobunaga.

In the 3rd year of Genki (1572), in response to a call from Yoshiaki Ashikaga, a shogun who had been hostile to Nobunaga, Shingen began invading Oda territory (Operation Seizyo (西上作戦)).

Nobutada continued to follow Oda Nobunaga, and fought in various places, such as the Ishiyama Hongan-ji War (石山戦争), the Siege of Iwamura Castle (岩村城の戦い) in February 1574, and the attack on Ise Nagashima from July to September 1574.

In 1582, he defeated Nishina Morinobu in the Siege of Takato[1] and participated in the Battle of Tenmokuzan against Takeda Katsuyori.

On November 28, 1576, Nobunaga handed over the Oda clan's lord, eastern Mino, and part of Owari Province, and was entrusted with its control.

In the same year, he was placed under the fifth rank (正五位), and he was appointed to Dewasuke (出羽介) and then Akita Josuke(秋田城介), aiming to become a shogun.

In February of the 5th year of Tensho (1577), Nobutada attacked Nakano Castle and captured it, and in March, Suzuki Shigehide (Sonichi Saika) and others surrendered to him .

On October 4, 1578, Saito Toshiharu, Nobutada's uncle-in-law, was dispatched by Nobunaga as the general reinforcement of Jinbo Nagazumi.

In the 10th year of Tensho (1582), Nobutada began the conquest of Koshu (Kai province) by leading an army of 50,000 Mino and Owari troops.

In the Siege of Takato castle, Nobutada stood at the forefront of his army and rushed into the moat, breached a barrier, climbed onto the rampart, and inspired his soldiers to attack.

[2] Takeda Katsuyori could not regain his position due to Nobutada's rapid advance and withdrew from Suwa.

In 1582, his father was forced to commit suicide when one of his generals, Akechi Mitsuhide attacked him while he was staying at Honno-ji, a Buddhist temple in Kyoto.