Finding a balance between her German-Italian mother's apartment in New York City and the Washington, D.C., home of her third-generation Japanese father was a task, but it readied Yamagata for a way of life that would eventually lead her to a professional singing career. By the time she reached college in the mid-'90s, Yamagata had one year of piano lessons and a spiral notebook full of songs under her belt.
Not sure of what she really wanted to do, Yamagata headed to Northwestern to study French. Within a year, she switched to being an Italian theater major at Vassar, but sporadic changes loomed ahead. When her acting coach at Vassar moved to Barnard College at Columbia University, Yamagata thought she'd go too. She eventually decided to head back to Northwestern instead, to join their theater program. During her junior year, she befriended the funk band Bumpus. Bumpus was a mainstay on the club circuit in Chicago. From the start, Yamagata thought she'd like to be a part of the band. After seeing countless shows and attending band practices for several months, Yamagata finally landed a gig singing with Bumpus.
She'd spend six years writing and recording three albums with the band and touring the country. By 2001, Yamagata felt like her time with Bumpus had run its course. She had a solid batch of songs that weren't fitting in with the band's funkafied formula, so she went solo. In September 2002, Yamagata landed a deal with Arista's Private Music and her self-titled EP arrived in October. Her first full-length album, Happenstance, followed in June 2004.