[8][9] In 2008, David Campos was elected to the San Francisco Board of Supervisors, representing District 9 (Bernal Heights, Portola, and the Inner Mission), succeeding newly-elected State Assemblymember Tom Ammiano.

Mayor Gavin Newsom appointed Campos to the vacant supervisorial seat on December 4, 2008, one month before the other freshman supervisors were elected in November 2008.

[10] His predecessor, Ammiano, had resigned from the San Francisco Board of Supervisors in early December to start his tenure at the California State Assembly.

Campos introduced legislation in August 2009 that sought to protect undocumented immigrant youths from deportation and separation from their families by the San Francisco police.

CleanPowerSF is a publicly owned clean energy program that allow residents to choose to buy electricity generated from renewable source rather than from PG&E, the dominant utility in the city.

[14] Ultimately, the plan will use the program’s revenue stream to help construct the city’s own renewable energy infrastructure, including wind and solar generators.

[22][23] In April 2016, Campos introduced legislation that would fine short-term rental companies such as Airbnb $1000 a day for each listing that wasn't registered with the City of San Francisco.

[24] After the Board of Supervisors approved the legislation, Airbnb sued the City, claiming that the law violated the Communications Decency Act, which prohibits the government from holding websites accountable for the content published by users.

By September 2021, Campos had announced his intention to run for the 17th Assembly District seat that would be vacated by David Chiu when he would become San Francisco City Attorney.

In a letter to the California Secretary of State, Matt Haney challenged the accuracy of that statement, arguing that the role of a DA’s chief of staff is to oversee operations and administration, not practice law.

[31] In March 2017, Campos was named one of seven deputy executives for Santa Clara County to lead the Division of Equity & Social Justice focused on LGBTQ, immigration, cultural competence, labor, and Census issues.

[35] In an interview, Campos cited the long commute to Santa Clara, and the opportunity to work on meaningful criminal justice reform as motivation to take the new job.