Her songs have appeared on numerous television shows and she has collaborated with Jason Mraz, Rhett Miller, Bright Eyes, Ryan Adams, Toots and the Maytals, Ray Lamontagne and Matt Nathanson.

[4][5] Yamagata was born to a Japanese American father and an Italian-German mother and grew up with comedian-actor Josh Ruben as a half-brother.

[8][9] Yamagata became the vocalist for the Chicago group Bumpus and spent six years touring, writing and recording with the band before leaving in 2001 to begin a solo career.

Yamagata was featured on the album True Love by Toots and the Maytals, which won the Grammy Award in 2004 for Best Reggae Album, and showcased many notable musicians including Willie Nelson, Eric Clapton, Jeff Beck, Trey Anastasio, Gwen Stefani / No Doubt, Ben Harper, Bonnie Raitt, Manu Chao, The Roots, Ryan Adams, Keith Richards, Toots Hibbert, Paul Douglas, Jackie Jackson, Ken Boothe, and The Skatalites.

[15] That month, her two-song live acoustic video performance appeared on LiveDaily Sessions and featured the songs "Faster" and "Sunday Afternoon".

[20] Yamagata contributed writing, keyboards and vocals to the song "Kaleidoscope" by Jill Cunniff a former member of Luscious Jackson.