Lifespan: Tenbun 18 (1549) to 1/11 of Keichō 12 (1607)
Other Names: Zengorō, Zenzaemon, Zenbei (common)
Lord: Tokugawa Ieyasu
Father: Aoyama Shigenari
Siblings: Masanaga, Shigetsugu, Masanari
Wife: Daughter of Ōkubo Tadamasu
Children: Shigenaga, daughter (wife of Gotō Mitsutsugu), daughter (wife of Aoyama Shigekatsu), daughter (wife of Aoyama Toshimasa)
Aoyama Masanaga served as a bushō during the Sengoku and Azuchi-Momoyama periods. He was a retainer of Tokugawa Ieyasu.
Masanaga made contributions during the Battle of Mikata-ga-hara and the Battle of Nagashino. Thereafter, he served in numerous battles for the pacification of Tōtōmi, Suruga, and Kai provinces. He further served meritoriously at the Battle of Komaki-Nagakute and the Conquest of Odawara. In 1600, Masanaga, together with his lineal heir, Aoyama Shigenaga, participated in the Second Battle of Ueda.
In 1601, when the granddaughter of Tokugawa Ieyasu, Tamahime, wed Maeda Toshitsune, Masanaga served as a deputy official and received an increase of his fief to a total of 2,000 koku.