A Democrat, she represents the 77th Assembly District, which encompasses coastal parts of northern San Diego County and the city of San Diego, including Carlsbad, Encinitas, Solana Beach, Del Mar, and the coastal communities of La Jolla south to Downtown and Coronado.

Prior to being elected to the State Assembly, she served on the Encinitas City Council.

Boerner was first elected to the State Assembly in November 2018 after defeating fellow Democrat Elizabeth Warren, a freelance journalist, not related to the former Presidential candidate of the same name.

In 2022, Boerner announced her intention to seek election to a third term, this time for the 77th district following redistricting.

In 2022, she was opposed in the general election by Republican entrepreneur and investment advisor Dan Downey.