A member of the Liberal Democratic Party, she was previously the vice president of the House of Councillors from 2007 to 2010.

She was the grandniece of Kodama Ryōtarō (1872 – 1921), who served in the House of Representatives during the Taishō era.

[1] On the recommendation of the composer Ikuma Dan, a friend of her mother, Santo became the host of a TBS Radio children's program at the age of eleven.

[3] Santo was elected to the House of Councillors for the first time in 1974 after working as an actress and reporter.

She had known the landowner (Kurihara family) for 30 years, and in 2011 he told her that he wanted to sell to the governor of Tokyo, Shintaro Ishihara (whose nationalistic book he liked), instead of to the government and the prime minister, Yoshihiko Noda.