During his two terms as Obama's vice president, Biden frequently represented the administration in negotiations with congressional Republicans and was a close counselor to Obama.
Biden and his running mate, Kamala Harris, defeated incumbents Donald Trump and Mike Pence in the 2020 presidential election. On January 20, 2021, he became the oldest president in U.S. history, the first to have a female vice president and the first president from Delaware. As president, Biden has addressed the COVID-19 pandemic and subsequent recession. He signed the American Rescue Plan Act, the bipartisan Infrastructure Investment and Jobs Act, the Inflation Reduction Act, and the Respect for Marriage Act, which codified protections for same-sex marriage and repealed DOMA. He appointed Ketanji Brown Jackson to the Supreme Court. In foreign policy, Biden restored America's membership in the Paris Agreement on climate change. He completed the withdrawal of U.S. troops from Afghanistan that had been negotiated and begun under the previous administration, ending the war in Afghanistan, during which the Afghan government collapsed and the Taliban seized control. He responded to the 2022 Russian invasion of Ukraine by imposing sanctions on Russia and authorizing foreign aid and weapons shipments to Ukraine.

