I'll bet you that the answer within the last 100 years time frame is "Ralph Nader".
Teddy Roosevelt's election to the Presidency
John McCain
Andrew Jackson was the presidential candidate in 1824 that seemed to relate to, and appeal to, the common man. Jackson received 41. 4 percent of the vote in the election.
Henry Clay
Nixon
The political figure to which you refer is the candidate William Jennings Bryan, famous for his "Cross of Gold" speech
Belva Ann Lockwood was the first woman candidate for president whose name appeared on some official ballots. Victoria Woodhull ran earlier but was underage for the presidency at the time and so was even less serious as a candidate than Lockwood. She got fewer than 500 popular votes. Hillary Clinton was the first serious candidate in 2008.
The candidates in 1912 were the incumbent Republican,Wm. Howard Taft, the Democratic candidate, Woodrow Wilson and ex-president, Theodore Roosevelt who ran as a third-party ( Bull-Moose) candidate. Roosevelt got more votes than Taft but not enough to beat Wilson.
Andrew Jackson first ran for the Presidency in 1824. After not being elected, Jackson ran again in 1828, and took office in 1829.
Wendell Wilkie ran against Roosevelt in 1940.
The first successful third party candidate in the United States was Abraham Lincoln, who ran as a Republican in the 1860 presidential election and won. His victory marked a significant shift in American politics as it was the first time a third party candidate had won the presidency.
James A. Garfield ran for office multiple times throughout his political career. He was elected to the Ohio State Senate and later served in the U.S. House of Representatives, where he held office for nearly two decades. Garfield ran for the presidency in 1880, which he won, making it his most significant electoral campaign. Overall, he had several candidacies at various levels, but the presidential run was the most notable.