A US senator from California the past four years, Harris has shattered many a glass ceiling. She served as San Francisco's first female district attorney and was California's first woman of colour to be elected attorney general.
She was sworn in by US Supreme Court Justice Sonia Sotomayor, the court's first Latina member.
Looking ahead, Harris, 56, is seen as an obvious contender for the Democratic Party's 2024 presidential nomination should Biden, 78, decide not to seek a second term. Harris has yet to weigh in publicly on such speculation.
