Supervisor Katy Tang won the sole contested candidate race on Tuesday's ballot, keeping her in office to represent the Sunset district for at least four more years.
Tang beat Ivan Seredni to be elected for the first time to the seat on the Board of Supervisors after being appointed by Mayor Ed Lee in February.
Tang was named to the post when her predecessor, Carmen Chu, was appointed by Lee to be assessor-recorder. Chu ran unopposed for that seat in Tuesday's election.
San Francisco City Attorney Dennis Herrera and Treasurer Jose Cisneros also ran unopposed and retained their seats in Tuesday's election.
