Former union leader and Democratic insider Laphonza Butler was sworn in as the newest member of the Senate on Tuesday, replacing California Sen. Dianne Feinstein after her death and becoming only the third Black female senator in history.

READ MORE: Who is Laphonza Butler, California’s Newest Senator?

Butler was appointed by California Gov. Gavin Newsom on Sunday, just two days after Feinstein died at her home in Washington. Butler is a longtime fundraiser and strategist in the state’s Democratic circles and was the head of EMILY’s List, a national organization that raises money for women candidates who support abortion rights.

On the Senate floor Tuesday, Butler was sworn in by Vice President Kamala Harris, who served as the second Black female senator until she resigned in 2021 to join President Joe Biden in the White House. The first was Democratic Sen. Carol Moseley Braun of Illinois, who served one term in the 1990s.

The Congressional Black Caucus was also holding a ceremonial swearing-in for Butler. "Her background and years of experience will bring a much-needed perspective to the Senate, which currently does not have any Black women,” caucus Chairman Steven Horsford, D-Nev., said in a statement after she was appointed.

Butler is also the first openly LGBTQ+ senator from California.

Though she has never held elective office, Newsom praised her “deep knowledge” of the legislative process and said she was the kind of candidate he would build “if I had to literally design from my imagination.”

“She’s the only choice,” Newsom added.

Butler is well known inside California’s Democratic Party apparatus. Her credentials include working for nearly two years with a consulting firm tied closely to Newsom and founded by his top political lieutenants. She also served as a senior adviser to Harris’ 2020 presidential campaign.