Born in 1559 as Tokugawa Ieyasu's eldest son. His mother was Lady Tsukiyama. Intelligent and brave from childhood, he was the great hope of the Tokugawa future. In 1568 he married Tokuhime (Goku), Oda Nobunaga's daughter, cementing the Oda-Tokugawa alliance. He was lord of Okazaki Castle and held the full confidence of the Mikawa retainers. In 1579 Nobunaga abruptly sent a letter demanding Nobuyasu's execution. Ieyasu complied and ordered his own son to commit seppuku. Nobuyasu died at Futamata Castle at age 21. Theories for the cause range from a secret letter sent by his wife Tokuhime to Nobunaga, to concerns about Nobuyasu's conduct. His death is recorded as one of Ieyasu's deepest regrets.

A promising young warrior praised as bright and brave—some said of even greater caliber than Ieyasu himself. His brief life leaves his true character veiled by history, making him the subject of many later stories and plays.

The tragedy of Nobuyasu became the subject of many later artistic works including Kabuki, Joruri, and novels. Historic sites related to him remain at Futamata Castle ruins and Seiryu-ji temple in Hamamatsu, Shizuoka.