Blanca Alvarado was born 1931. The daughter of a coal miner who was active in the union, she was born in the Colorado mining town of Cokedale. After the mine's closure, the family moved to the Santa Clara Valley in California. Alvarado worked with Cesar Chavez to establish the Community Services Organization and was involved with the Chicano Employment Committee and the Opportunities Industrial Center. She was president of the local chapter of the Mexican American Political Association and was also an officer at the state level.

In 1980, she was elected to San Jose City Council, representing East San Jose until 1994. Alvarado served two terms as San Jose's first Latina vice mayor. In 1995, she was appointed to fill a vacant position in the Santa Clara County Board of Supervisors after Zoe Lofgren was elected to Congress. Alvarado was elected to a full term on the Board of Supervisors in March 1996, where she served through 2008. In 1998, Alvarado became the first Latina Chairperson in the County's Board of Supervisors.

Alvarado served on the Children and Families' Committee and Public Safety and Justice Committee. She was active in efforts to improve Santa Clara County's juvenile detention system. She also established an Office of Women’s Advocacy for the county to develop programs to help women develop in their professional and personal lives.

In 2002, Alvarado was awarded the Woman of the Year Award by the San Francisco Bay Area Chapter of the Women’s Transportation Seminar, an international organization dedicated to the professional advancement of women in transportation, recognizing her contributions as a member of the board for the Santa Clara Valley Transportation Authority. In 2012, Alpha: Blanca Alvarado Middle School in the San Jose Alum Rock neighborhood was named in her honor to recognize her work as a community activist.