Abe Masayoshi served as a bushō during the Sengoku and Azuchi-Momoyama period. He was a retainer of the Uesugi clan.
His origins are unknown but he served Uesugi Kagekatsu and fought in numerous battles. In 1580, Masayoshi and his son, Abe Yoshizane, entered Tochio Castle in Echigo Province. Before long, he went to Etchū Province. In 1581, Masayoshi, together with Yoshizane, Yoshie Munenobu and Nakajō Kageyasu, defended Uozu Castle.
In 1582, during the Siege of Uozu Castle, he warded-off an attack by Shibata Katsuie, a senior retainer of the Oda Nobunaga, and temporarily repelled the enemy forces, but in the end the castle fell and, together with the commander of the castle, he took his own life.