Incumbent Democratic Senator Barbara Boxer decided to not run for reelection to a fifth term.

Harris did not serve her full term in the Senate, as she resigned on January 18th, 2021 after being elected Vice President of the United States in 2020.

Governor Gavin Newsom appointed Alex Padilla, the incumbent Secretary of State of California, to serve the rest of her term.

[234] Harris stepped down from her Senate seat on January 18, 2021, two days before her inauguration as vice president.

Harris is the second incumbent US senator from this seat to be elected vice president, the first being Richard Nixon in 1952.