BOSS was founded in 1971 by a group of volunteers from the Hillel Streetwork Project in Berkeley who responded to the needs of mentally ill individuals being released to the streets by state hospital closures. Volunteers provided street outreach, crisis intervention, and benefits advocacy to the emerging homeless population. Founding Board Member and civil rights activist Ursula Sherman raised money to pay the first project staff, and the organization was incorporated as a 501c3. 

Today, BOSS maintains its mission housing individuals with severe and persistent mental illness and further develops solutions to mass homelessness, mass incarceration and community violence and is dedicated to the inclusion of people marginalized by addiction, trauma, criminality, incarceration, poverty, racism, sexism, homelessness and violence with an intentional focus on four areas of service with Housing Security, Criminal Justice Reentry, Neighborhood Safety, and Social Justice programs and services.

BOSS continues its County-wide expansion, adding programs in response to changing needs to include a suite of emergency and permanent housing installations as well as Neighborhood Impact Centers in the heart of impacted communities with employment, education, housing and peer support, social justice and leadership development programming.