The Crystal Ball finds that 31 of 43 U.S. presidents had been defeated in elections at least once on their way to the White House.

“Remarkably, two presidents were defeated three times (William McKinley and George H.W. Bush), and four others lost four times (William Henry Harrison and his grandson, Benjamin Harrison, as well as one of our best presidents, Abraham Lincoln; and one of our worst, James Buchanan).”

“Of the 12 presidents who entered the White House with an undefeated electoral record, Gerald Ford is the most recent. Of course, he wasn’t elected president — or vice president, for that matter — and his victories consisted entirely of a string of U.S. House wins from 1948 to 1972 in his Grand Rapids, MI district. The last elected president who won every prior political contest was Woodrow Wilson. Of course, Wilson wasn’t a professional politician and had only run once before gaining the presidency, for governor of New Jersey in 1910. (Dwight Eisenhower isn’t included, since he never ran at all before his elevation to the White House.)”
Taegan Goddard’s Political Wire