In a development that sends the contest into unchartered territory, the US president announced that he will no longer be seeking a second term.
Instead, another Democrat will now need to be chosen to face off against Republican nominee Donald Trump in November in a race that has already been marked by tension, division and an assassination attempt.
In a letter addressed to “my fellow Americans”, he said it had been the “greatest honour of my life to serve as your president”.
“While it has been my intention to seek reelection, I believe it is in the best interest of my party and the country for me to stand down and to focus solely on fulfilling my duties as president for the remainder of my term.”
He has endorsed Kamala Harris as the Democratic nominee, saying: “Democrats – it’s time to come together and beat Trump.”
In the letter posted on X he wrote: “I will speak to the Nation later this week in more detail about my decision.
“For now, let me express my deepest gratitude to all those who have worked so hard to see me reelected.
“I want to thank Vice President Kamala Harris for being an extraordinary partner in all this work. And let me express my heartfelt appreciation to the American people for the faith and trust you have placed in me.
“I believe today what I always have: that there is nothing America can’t do – when we do it together. We just have to remember we are the United States of America.”
Mr Biden’s wife Jill Biden reposted the statement on X with a loveheart.
