Kushibuchi sailed on the Peace Boat for the first time in 1990,[1] and later joined the associated nongovernmental organization as an executive.

[2] In 2009, she contested her first House of Representatives election and won Tokyo's 23rd district for the Democratic Party of Japan.

[3] Kushibuchi lost her 2012 reelection bid to Masanobu Ogura.

[4] Following the 2022 resignation of Tarō Yamamoto, Kushibuchi returned to the House of Representatives via proportional representation, this time as a member of Reiwa Shinsengumi.

[5][6] On 1 June 2023, she was suspended from participating in the Diet for 10 days for "irregular behavior" in the lower chamber, which involved holding up a sheet of paper calling the no-confidence motion against Finance Minister Shun'ichi Suzuki a farce, while standing on the rostrum.