Joseph Robinette Biden Jr. (born November 20, 1942) is an American politician who is the 46th and current president of the United States since 2021. A member of the Democratic Party, he served as the 47th vice president from 2009 to 2017 under President Barack Obama and represented Delaware in the U.S. Senate from 1973 to 2009.

Born in Scranton, Pennsylvania, Biden moved with his family to Delaware in 1953. He graduated from the University of Delaware in 1965 before earning his law degree from Syracuse University in 1968. He was elected to the New Castle County Council in 1970 and the U.S. Senate in 1972, as one of the youngest Senators in history. As a senator, Biden drafted and led the effort to pass the Violent Crime Control and Law Enforcement Act and the Violence Against Women Act. He also oversaw six U.S. Supreme Court confirmation hearings, including the contentious hearings for Robert Bork and Clarence Thomas. Biden ran unsuccessfully for the 1988 and 2008 Democratic presidential nominations. In 2008, Obama chose Biden as his running mate, and he was a close counselor to Obama during his two terms as vice president. In the 2020 presidential election, the Democratic Party nominated Biden for president. He selected Kamala Harris as his running mate and defeated Republican incumbent Donald Trump. He is the oldest president in U.S. history and the first to have a female vice president.

As president, Biden signed the American Rescue Plan Act in response to the COVID-19 pandemic and subsequent recession. He signed bipartisan bills on infrastructure and manufacturing. He proposed the Build Back Better Act, which failed in Congress, but aspects of which were incorporated into the Inflation Reduction Act that he signed into law in 2022. Biden appointed Ketanji Brown Jackson to the Supreme Court. He worked with congressional Republicans to resolve the 2023 debt-ceiling crisis by negotiating a deal to raise the debt ceiling. In foreign policy, Biden restored America's membership in the Paris Agreement. He oversaw the complete withdrawal of U.S. troops from Afghanistan that ended the war in Afghanistan, leading to the collapse of the Afghan government and the Taliban seizing control. He responded to the Russian invasion of Ukraine by imposing sanctions on Russia and authorizing civilian and military aid to Ukraine. During the Israel–Hamas war, Biden condemned the actions of Hamas as terrorism, announced military support for Israel and sent limited humanitarian aid to the Gaza Strip.

In April 2023, Biden announced his reelection campaign. After the 2024 Democratic primaries, he became the party's presumptive nominee in the 2024 presidential election. But Biden withdrew his candidacy in July 2024 after a series of age and health concerns. He endorsed Harris to replace him as the nominee, while saying that he would remain president until the conclusion of his term.