Hatano Hideharu served as a daimyō and the last lord of the Hatano clan in Tanba Province during the Sengoku and early Azuchi-Momoyama periods.

Hideharu was the son of Hatano Harumichi.  After the death of his grandfather, Hatano Tanemichi, the Hatano clan served under Miyoshi Nagayoshi.  Hideharu also initially served the Miyoshi, attending the coronation ceremony of Emperor Tennō.  However, in 1566, following the death of Nagayoshi, Hideharu recaptured Yakami Castle, the home base of the Hatano clan, and became an independent sengoku daimyō in Tanba.  In his position as a son-in-law, Hideharu also forged an alliance with Bessho Nagaharu of Harima Province.   

In 1568, Hideharu submitted to the Oda clan after Oda Nobunaga marched to Kyōto in support of Ashikaga Yoshiaki as the nominal shōgun.  In 1575, Hideharu joined with forces under Akechi Mitsuhide who was sent by Nobunaga to subjugate wealthy families opposed to the Oda in Tanba.  However, behind the scenes, Hideharu made scrupulous efforts to communicate his intentions to cooperate with the wealthy families in Tanba.  Early in 1576, Hideharu suddenly rebelled against Nobunaga, and defended against an attack by Mitsuhide’s forces at the Siege of Kuroi Castle. 

Nobunaga then assigned a large contingent to Mitsuhide and ordered another attack in Tanba. Hideharu responded by taking refuge in Yakami Castle and, along with kokujinshū, or provincial landowners, who supported his rebellion, put up a stiff defense.  Hideharu had an intimate knowledge and understanding of the complex mountainous terrain in Tanba.  He skillfully exploited this tactical advantage by antagonizing the enemy forces, while the fierce attacks by the Oda endured for a year and a half.  As the stand-off wore on, supplies in the castle ran low and families in Tango and Tajima provinces were gradually defeated.  Through the devices of Mitsuhide, other families switched their allegiance to the Oda, making Hideharu’s situation increasingly perilous so that, in 1579, he finally surrendered to Mitsuhide.  

Thereafter, the Oda took Hideharu and his younger brother, Hatano Hidehisa, to Nobunaga’s home base in Azuchi Castle.  Upon orders of Nobunaga, they were executed by crucifixion at the Jōgonin of the Jion Temple on Mount Kinshō.