List of presidents of the United States by age
The median age upon accession to the presidency is 55 years and 3 months. This is how old Lyndon B. Johnson was at the time of his inauguration. The youngest person to assume the office was Theodore Roosevelt, who became president at the age of , following William McKinley's assassination; the oldest was Donald Trump, who was old at his inauguration. The youngest person to be elected president was John F. Kennedy, at of age on election day; the oldest was Ronald Reagan, who was old at the time of his election to a second term.
Inauguration of John F. Kennedy
Kennedy took office following the November 1960 presidential election, in which he narrowly defeated Richard Nixon, the then–incumbent Vice President. He was the first Catholic to become President, and became the youngest person elected to the office.