[1] A native of Tokyo and graduate of the law faculty of the University of Tokyo, he joined Industrial Bank of Japan in 1987, receiving MBA in 1992 from Stanford University while working at the bank.

Leaving the bank in 1995, he was elected to the House of Councillors for the first time in 1998 to represent Kanagawa Prefecture.

[2] He was re-elected in 2004, and was appointed the Shadow Foreign Minister by the DPJ leader Seiji Maehara.

He was later expelled from the DPJ after announcing he would run for a district seat in Kanagawa during the 2009 General election, joining Your Party as a founding member one month later.

[3] Taking helm of the party in April 2014 after a financial scandal touching its founder,[4] he voted in favor of disbanding it in November 2014 over dissension against plans to support the LDP.