Kau‘i Yamane was born and raised in Honolulu. As a high school student, she took her first job as a file clerk at Leavitt, Yamane & Soldner.
Kau‘i holds a BA.Sc degree in Communications from the University of Colorado at Boulder. In 2010, she earned her Juris Doctor degree from the University of Hawai‘i at Manoa's William S.Richardson School of Law, with certificates in Native Hawaiian Law and Environmental Law. As a student, she was an active participant in ‘Ahahui O Hawai‘i, the law school's Native Hawai‘i Student Organization. She also served as a coach to a mock trial team from McKinley High School, working with them to prepare both sides of a case that would be argued in competition with a team from another school.
Kau‘i began her legal career as deputy prosecutor in Honolulu's Department of the Prosecuting Attorney, preparing and presenting felony cases for Honolulu Grand Jury indictment and preliminary hearings, and successfully represented the State of Hawai‘i in felony and domestic violence jury trials.
After nearly four years with the prosecutor's department, Kau‘i took time off to get married and start a family with her husband in Washington, DC. While there, she served in the Volunteer Lawyer Project, helping domestic violence survivors obtain court ordered stay away orders and civil protective orders against their abusers. In 2020, as the pandemic was just getting started, she returned to Hawai‘i and joined Leavitt, Yamane & Soldner as a personal injury attorney.