He is thought to have attempted to raise the family status of the Kiyohara clan by getting Narihira married with a daughter of MINAMOTO no Yoriyoshi, the Toryo (leader) of the Minamoto clan.
その成衡に源氏棟梁である源頼義の娘を嫁がせることで清原氏の家格を高めようとしたとも考えられている。