US Senate minority leader Mitch McConnell will retire from his role as the top Republican in the upper chamber of Congress in November, he announced on Wednesday.
“I turned 82 last week. The end of my contributions are closer than I prefer,” Mr McConnell told the Senate.
“Father Time remains undefeated. I'm no longer the young man sitting in the back hoping colleagues remember my name. It's time for the next generation of leadership.”
The announcement is remarkably similar to longtime Representative Nancy Pelosi's move to step down as the Democratic leader in the House of Representatives in November 2022.
The decision was unrelated to his health, AP reported, after two public incidents in which he froze while speaking.
The Kentucky politician said the recent death of his wife's sister prompted a “certain introspection that accompanies the grieving process”.
US Senate's McConnell freezes up for second time in public appearance
It is not yet clear who will be his successor.
President Joe Biden said he was "sorry to hear" about Mr McConnell's announcement.
"We have a great relationship," Mr Biden said at the White House. "We fight like hell. But he has never, never, never misrepresented anything."
The President later issued a statement to commemorate the Republican leader's work.
"American Democracy is based on elected representatives coming together and bridging their different points of view to find common ground on behalf of the American people," he said.
"I’m proud that my friend Mitch McConnell and I have been able to do that for many years, working together in good faith even though we have many political disagreements."
"During his many years of leadership, we could always speak with each other honestly and put the country ahead of ourselves."
Mr McConnell's expected departure comes as the Republican Party shifts ever closer to former president and 2024 presumptive Republican nominee Donald Trump.
Mr McConnell is one of the few Republicans in the Senate not to endorse Mr Trump for this election.
He has faced increasing pressure from members of his party in recent months over his support for financial assistance to Ukraine.
He has openly supported a bipartisan $95 billion security package that would deliver assistance to Ukraine, Israel and Taiwan.
“Believe me, I know the politics within my party at this particular moment in time,” Mr McConnell said. "I have many faults. Misunderstanding politics is not one of them.
“That said, I believe more strongly than ever that America’s global leadership is essential to preserving the shining city on a hill that Ronald Reagan discussed.
"For as long as I am drawing breath on this earth, I will defend American exceptionalism.”
Mr McConnell had worked with Mr Trump and was instrumental in shaping the judiciary system, most notably in the Supreme Court's 6-3 conservative majority.
But his relationship with the former president disintegrated after the insurrection at the US Capitol on January 6, 2021.
Although he voted to acquit Mr Trump in impeachment proceedings, Mr McConnell placed the blame of the attack squarely on the former president.
The longest-serving Senate leader in US history, Mr McConnell has led the Republican Party there since 2007.
