Democratic US House Speaker Nancy Pelosi has announced she will not seek re-election as Democratic leader.
The 82-year old said she was stepping down in an emotional speech to the House on Thursday morning.
"I will not seek re-election," she confirmed, but said she will remain in her role as a member of Congress.
It follows last week's midterm elections in which the Republicans took control of the lower chamber.
"I never thought I would go from homemaker to House Speaker," she told the chamber, saying she "never intended" to run for public office.
The speaker's decades-long career in Congress shattered the glass ceiling, as she was the first woman to hold the role.
During her tenure, she oversaw sweeping reforms such as the Affordable Care Act and more recently, she led her party through a surprisingly successful midterm cycle.
President Joe Biden was among the first to sing her praises after the announcement.
"History will note she is the most consequential speaker of the House of Representatives in our history," Mr Biden said in a statement.
"Because of Nancy Pelosi, the lives of millions and millions of Americans are better, even in districts represented by Republicans who voted against her bills and too often vilify her."
Ms Pelosi spoke of various achievements during her long tenure, including those achieved alongside Mr Biden.
"When I came to Congress in 1987, there were 12 Democratic women. Now there are 90, and we want more," she added.
Ms Pelosi said voters "repelled the assault on democracy" when they went to the polls, in which the Democrats retained control of the Senate.
"American democracy is majestic, but is fragile ... democracy must be forever defended from forces which wish it harm," she told the House.
Her deputy chief of staff Drew Hammill said Ms Pelosi had been “overwhelmed” by calls from colleagues and supporters as she monitored incoming results from three key states on Wednesday night.
She acknowledged her husband, Paul, in an emotional moment during her Thursday speech on the House floor, during which fellow Democrats shed tears and members of both parties rose for a standing ovation.
Her husband was left injured after an intruder broke into their home earlier this month, said to have been waiting for Ms Pelosi.
"My dear husband, Paul, has been my beloved partner in life and my pillar of support. Thank you. We're all grateful for all the prayers and well wishes as he continues his recovery," the departing speaker said.
“I have to say my decision will be affected about what happened the last week or two,” she told CNN on her future plans in the aftermath of the attack.
Ms Pelosi was elected to the House in 1987, representing San Francisco's congressional district, and assumed her role as speaker for a first term in 2007. She was reelected in 2019.
Democratic colleagues, including Corey Booker, a New Jersey Senator, and fellow Hakeem Jeffries, quickly sent thanks and congratulations to Ms Pelosi.