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.
Theodore Roosevelt Jr.
Theodore "Ted" Roosevelt III (September 13, 1887 – July 12, 1944), known as Theodore Roosevelt Jr., was an American government, business, and military leader. He was the eldest son of President Theodore Roosevelt and First Lady Edith Roosevelt. Roosevelt is known for his World War II service, including the directing of troops at Utah Beach during the Normandy landings, for which he received the Medal of Honor.