When President Joe Biden was sworn into office on Jan. 20, 2021, he became the oldest person in U.S. history to assume the presidency.
Though the U.S. president holds the highest, most powerful office in the world, the Founding Fathers laid out very few requirements for someone to win the job. To become President of the United States, you must be a natural-born citizen (not a naturalized immigrant) who has lived here for 14 years and is at least 35 years old. There are no experience requirements, as evidenced by the fact that President Trump and several other presidents from the 1800s didn't hold political office before taking the White House.
It's unclear exactly why the founders set 35 as the minimum age limit—some historians think it was to avoid foreign influence in the executive or to keep families from creating huge political dynasties. However, with the 2020 election just around the corner, a new question has emerged: can someone be too old to run for president?
There's no constitutional cap on the president's age but as human lifespans continue to lengthen, it becomes an even more important question. Past polls suggested that the majority of Americans wouldn't vote for someone over 75—but that was disproven in the 2020 election. To learn more about the various ages of American presidents, Stacker ranked all 46 presidents from youngest to oldest at the time of their inauguration and took a look at their biographies to see how age and experience shaped each president's time in office.
Keep reading to see which young presidents came to office by accident (or not) and tried to change the country, and discover which president's wife secretly became commander-in-chief after health issues nearly ended his presidency early.
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