Los Angeles City Council member Nury Martinez resigned on Wednesday amid extreme pressure, including from the White House, after surreptitiously recorded racist comments about a colleague's son were made public.
“Serving you has been a privilege and one that I don’t give up lightly,” Ms Martinez said. “It’s hard to say goodbye but please know that I was in this fight for you.”
President Joe Biden said he wanted to see resignations from all three members who took part in the conversation.
"He believes that they all should resign," White House press secretary Karine Jean-Pierre said.
"The language that was used and tolerated during that conversation was unacceptable and it was appalling."
The turmoil began after a recording of racist and highly bigoted comments made by Latino members nearly a year ago were leaked to the public.
Ms Martinez, who landed in the centre of the storm, can be heard saying that a fellow council member, Mike Bonin, who is white, treated his young son, who is black, as an “accessory”, and that the child was like a monkey.
She also used a homophobic slur to denigrate Mr Bonin and called indigenous immigrants from the Mexican state of Oaxaca “tan feos,” or “so ugly”.
Ms Martinez, the first Latina appointed president of the city council, was speaking with at least two other council members, Kevin de Leon and Gil Cedillo, who can be heard laughing and taking part.
Mr de Leon and Mr Cedillo remain in their council seats.
At a Tuesday council meeting, protesters shouted at Mr de Leon and Mr Cedillo to leave the room.
A hush fell over the room as Mr Bonin came to the podium.
"Asking for forgiveness is a good first step first — well, it’s the second step because first you must resign and then ask for forgiveness," he said as the crowd cheered.
Other calls for the council members to resign have come from across the Democratic establishment, including from US Senator Alex Padilla, Los Angeles Mayor Eric Garcetti, mayoral candidates Karen Bass and Rick Caruso, and other members of council.
Governor Gavin Newsom denounced the racist language, saying he was “encouraged that those involved have apologised and begun to take responsibility for their actions", but fell short of demanding resignations.
California Congressman Jimmy Gomez met Ms Bass in "an emergency meeting with civic, faith and justice leaders to start the process of coming together and healing".
"I am appalled by the racist, homophobic language and personal attacks made in a leaked audio recording of a meeting with city council officials," Mr Gomez said in a letter to constituents.
"There’s no room for anti-blackness, anti-LGBTQ, anti-indigenous language in any shape or form. We must root it out. LA is hurting, and these past days have been painful."
The California Legislative Black Caucus said the recording “reveals an appalling effort to decentralise black voices during the critical redistricting process".
Mr Biden on Wednesday begins a three-day trip of the US western states of Colorado, California and Oregon.