Nanyang, Henan
Zhao Zongru was born in 746, during the reign of Emperor Xuanzong. His family was from Deng Prefecture (鄧州, in modern Nanyang, Henan) and traced its ancestry to the Northern Wei general Zhao Tong (). Other male-line ancestors of Zhao Zongru's served as officials under Northern Wei, Sui Dynasty, and Tang Dynasty, including his father Zhao Hua ().