Shimazu Tadakado served as a bushō during the late Muromachi and early Sengoku periods.  He was the second head of the Shimazu-Hōshū family.

In 1453, Tadakado, together with his father, Shimazu Suehisa, attacked the Kamō clan at Kamō Castle and brought the area of Kamō under their control.  In 1473, after Shimazu Hisayasu of the Shimazu-Izaku family revolted, Tadakado was initially neutral, but then suddenly rebelled against Shimazu Tadamasa, the eleventh head of the main branch of the Shimazu family.  Upon the urging of Shimazu Kunihisa of the Shimazu-Sasshū family and Sagara Tametsugu of Higo Province, Tadakado supplied troops and, after Hisayasu came to attack Kagoshima, Tadakado obeyed Tadamasa and repelled Hisayasu’s forces.

In 1486, upon orders of Tadamasa, Tadakado was granted the base of the Niiro clan at Obi Castle and the Shimazu-Izaku family at Kushima Castle.  Upon entering Obi Castle, he halted repeated invasions by the Itō clan of Hyūga Province.  In 1491, he died at the the Settsu-Tennō Temple.  He was fifty-two years old.

Tadakado received secret teachings from a renga master named Sōgi in regard to the kokin-waka, a compilation of waka, and the Ise mongatari, a collection of short Heian-period tales in the form of poems.  He further received instruction from Keian Genju, a priest of the Rinzai sect, in neo-Confucianism (based on the teachings of Zhu Xi and his followers)​.