Joe Biden's tenure as the 46th president of the United States began with his inauguration on January 20, 2021, and ended on January 20, 2025. Biden, a member of the Democratic Party who previously served as vice president for two terms under President Barack Obama from 2009 to 2017, took office after his victory in the 2020 presidential election over the incumbent president, Donald Trump of the Republican Party. Upon his inauguration, he became the oldest president in American history, breaking the record set by Ronald Reagan. Alongside Biden's presidency, the Democratic Party also held their slim majorities in the House of Representatives under Speaker Nancy Pelosi and the Senate under Senate Majority Leader Chuck Schumer during the 117th U.S. Congress. Biden entered office amid the COVID-19 pandemic, an economic crisis, and increased political polarization.