Joe Biden get sworn in as the 46th president of
Watch Joe Biden get sworn in as the 46th president of the United States
Joe Biden get sworn in as the 46th president of the United States. Joe Biden, 78, officially became the oldest president of the United States in the nation's history when he was sworn in as commander in chief Wednesday. His predecessor, President Donald Trump, previously held the record as the oldest ever to become president. Trump was 70 years old for his inauguration on Jan. 20, 2017.