Longtime Republican Sen. Mitch McConnell announced on Thursday he will not seek reelection next year. McConnell, who turned 83 today, was largely expected to end his Senate tenure at the conclusion of his term in January 2027 but made it official in a floor speech in which he reflected on his decades-long political career. "Seven times my fellow Kentuckians have sent me to the Senate. Every day in between I have been humbled by the trust they place in me to do their business, right here," he said. "Representing our commonwealth has been the honor of a lifetime." "I will not seek this honor for an eighth time," he continued. "My current term in the Senate will be my last." McConnell was met with a standing ovation from colleagues after his remarks. McConnell stepped down from his role as party leader last year after a record-breaking 18 years atop the GOP conference. He said Thursday that serving in the role was "a rare and, yes, rather specific childhood dream" come true. Since ending his tenure as leader, McConnell has distinguished himself as one of few Republican senators willing to challenge President Donald Trump. He has voted against three of Trump's Cabinet nominees so far, more than any other GOP lawmaker in the body. On Thursday, McConnell noted the "weight" of the Senate's responsibility to advise and consent has never been lost on him. The senator described arriving on Capitol Hill without executive experience or a background in Washington dynamics. He's since become the ultimate institutionalist and had an immense impact on shaping the federal judicial system. He led the Senate in the confirmation of hundreds of judges and three Supreme Court justices. He also permanently altered the Senate rules for confirming Supreme Court justices. Now, with the reliance of courts to act as non-political arbitrators continues to be questioned, McConnell offered a warning to the Senate about the need to continue an objective confirmation process. "We're trusted, on behalf of the American people, to participate in the appointment of the federal judiciary. To be the final check on the assembly of power in accordance beyond the reach of representative politics and to ensure that the men and women who preside over them express authentic devotion to the rule of law above all else," McConnell said. "When members of this body ignore, discount, or pervert this fundamental duty they do so not just at the peril of the senate but of the whole nation." PHOTO: Republican Senator from Kentucky Mitch McConnell is wheeled into the US Capitol to make a formal announcement that he won't seek re-election in 2026 in Washington, DC, Feb. 20, 2025. Republican Senator from Kentucky Mitch McConnell is wheeled into the US Capitol to make a formal announcement that he won't seek re-election in 2026 in Washington, DC, Feb. 20, 2025. Jim Lo Scalzo/EPA via Shutterstock McConnell spent time discussing national defense, saying he'll use his remaining time in office to complete the "unfinished business" of restoring America's strength through deterrence and partnership. As he closed his remarks, McConnell expressed optimism for the future of the Senate. "Regardless of the political storms that may wash over this chamber, during the time I have remaining, I assure our colleagues that I will depart with great hope for the endurance, the endurance of the Senate as an institution," he said. "There are any number of reasons for pessimism. But the strength of the Senate is not one of them." ABC News' Alexandra Hutzler contributed to this report.