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.
Presidency of John F. Kennedy
On November 8, 1960, Kennedy defeated Nixon in one of the closest presidential elections of the 20th century. Kennedy won the popular vote by a narrow margin of 120,000 votes out of a record 68.8 million ballots cast. He won the electoral vote by a wider margin, receiving 303 votes to Nixon's 219. 14 unpledged electors from two states—Alabama and Mississippi—voted for Senator Harry F. Byrd of Virginia, as did one faithless elector in Oklahoma. In the concurrent congressional elections, Democrats retained wide majorities in both the House of Representatives and the Senate. Kennedy was the first person born in the 20th century to be elected president, and, at age 43, the youngest person elected to the office. He was also the first Roman Catholic elected to the presidency.