San Francisco would be having its first-ever female black mayor - at a time when African-Americans are becoming increasingly scarce in the US city.
London Breed, a long-time community activist who grew up in public housing, was announced as the winner after her rival admitted defeat a week after city voters cast their ballots.
Winning with just over 50% of votes, the 43-year-old said she felt humbled.
Breed is the only female mayor to serve in the top 15 largest US cities.
She told the newspaper: "Five of us living on $900 per month. 'Recycling' meant drinking out of old mayonnaise jars. Violence was never far away.
"And once a week, we took Grandma's pushcart to the community room to collect government-issued groceries."