Gerald Ford is the only United States President who was not elected to national office – neither as President or Vice President.
Gerald Ford was nominated by President Richard Nixon to serve as Vice President when Spiro Agnew resigned from his position. Ford served from 1973 to 1974, until Nixon resigned from office. Ford assumed the presidency, since he was next in the line of succession.
President Ford ran for another term in the 1976 Presidential Election, but faced stiff resistance after pardoning Nixon. Ford lost to Jimmy Carter, 50.1% to 48%.
Take a look at his political campaign ad from 1976: