His father was Prince Takechi and his mother Princess Minabe (a daughter of Emperor Tenji and Empress Genmei's sister).

Fujiwara no Fuhito, the leader of the house, had been the most powerful courtier in the court in the days when Japan was under the reign of Empress Genshō, a cousin of Nagaya's.

This power shift was the source of later conflicts between him and Fuhito's four sons (Muchimaro, Fusasaki, Maro and Umakai) in the reign of Emperor Shōmu.

In 729, the four sons charged him with a false crime and Nagaya received the death penalty.

Parents Consorts and issue It is said that, as Prince Nagaya was forced to die unreasonably, he bore a grudge against the living after his death.