List of Presidents of the United States Under the United States Constitution , the President of the United States is the head of state and head of government of the United States . As chief of the executive branch and head of the federal government as a whole , the presidency is the highest political office in the United States by influence and recognition . The president is also the commander - in - chief of the United States Armed Forces . The president is indirectly elected to a four - year term by an Electoral College ( or by the House of Representatives should the Electoral College fail to award an absolute majority of votes to any person ) . Since the ratification of the Twenty - second Amendment to the United States Constitution in 1951 , no person may be elected President more than twice , and no one who has served more than two years of a term to which someone else was elected may be elected more than once . Upon the death , resignation , or removal from office of an incumbent President , the assumes the office . The President must be at least 35 years of age , has to live in the United States for 14 years , and has to be a " natural born " citizen of the United States . This list includes only those persons who were sworn into office as president following the ratification of the United States Constitution , which took effect on March 4 , 1789 . For American leaders before this ratification , see President of the Continental Congress . The list does not include any Acting Presidents under the Twenty - fifth Amendment to the United States Constitution . There have been 43 people sworn into office , and 44 presidencies , as Grover Cleveland served two non - consecutive terms and is counted chronologically as both the 22nd and 24th president . Of the individuals elected as president , four died in office of natural causes ( William Henry Harrison , Zachary Taylor , Warren G . Harding , and Franklin D . Roosevelt ) , four were assassinated ( Abraham Lincoln , James A . Garfield , William McKinley , and John F . Kennedy ) and one resigned ( Richard Nixon ) . George Washington , the first president , was inaugurated in 1789 after a unanimous vote of the Electoral College . William Henry Harrison spent the shortest time in office with 32 days in 1841 . Franklin D . Roosevelt spent the longest with over twelve years , but died shortly into his fourth term in 1945 ; he is the only president to have served more than two terms . A constitutional amendment , affecting presidents after Harry Truman , was passed to limit the number of times an individual can be elected president . Andrew Jackson , the seventh president , was the first to be elected by men of all classes in 1828 after most laws barring non - land - owners from voting were repealed . Warren Harding was the first elected after women gained voting rights in 1920 . History records four presidents – John Q . Adams , Rutherford B . Hayes , Benjamin Harrison and George W . Bush – who lost the popular vote but assumed office . John F . Kennedy has been the only president of Roman Catholic faith , and the current president , Barack Obama , is the first president of recent African descent . Living former presidents . As of 2018 , there are four living former presidents : The most recent death of a former president was that of Gerald Ford ( 1974 – 77 ) on December 26 , 2006 , aged 93 .