Why were the Whigs successful in capturing the presidency in 1840. Aside from tapping a war hero, were there other factors?
The superficiality of the election has been pointed out by both previous posters. The campaign's romanticizing Harrison and his "cider" penchants and his depiction as being of the common man was ripped from Jacksonian Democracy. The real issue which allowed the Whigs to mobilize nearly a million new voters into the process was the anger felt at economic disenfranchisement. In the new industrial conception of America, very few were being made extremely wealthy at the cost of many more. There was a level of palpable rage at this economic state of affairs, and the Whigs were able to tap into this anger as they depicted Van Buren as out of touch and unwilling or unable to assist. As the economic trouble mounted, the incumbent Democrats were drawn up to be completely insufficiently equipped to handle the challenge, provoking the need for change and new leadership.
I would say that other than having a war hero, the Whigs profited from what we would now call the populist vote. They were lucky to be able to cast themselves as the party of the little guy against the Democratic elites.
What happened was that a Democratic newspaper said something about Harrison wanting to spend his time drinking cider on the porch of his log cabin. From this, the Whigs were able to play up Harrison as a man of the people who had a log cabin and liked "hard cider." They made this a major campaign slogan, implying that Harrison was just a regular guy even though he was from a rich Virginia family.
The election of 1840 signaled the emergence of a permanent two-party system in the United States. For the next decade, Whigs and Democrats evenly divided the electorate. Although there was much overlapping, both parties attracted distinct constituencies and offered voters a clear choice of programs. The Whigs stood for a “positive liberal state,” which meant active government involvement in society. The Democrats stood for a “negative liberal state,” which meant that the government should intervene only to destroy special privileges. Both parties shared a broad democratic ideology, but the Democrats were the party of the individual, while the Whigs were the party of the community.
In 1840 the Whigs were fully organized and had learned the art of successful politicking. They nominated William Henry Harrison, a non-controversial war hero, and built his image as a common man who had been born in a log cabin. As his running mate, the Whigs picked John Tyler, a former Jacksonian, because he would attract some votes from states'-rights Democrats. Harrison and Tyler beat Van Buren, although the popular vote was close.
The Whigs were also successful because they sponsored large public meetings and made great use of symbolism and imagery. Harrison rode to victory on his slogan “Tippecanoe and Tyler Too” and his false image of common log cabin origins. He never stated his goals, nor did the Whig party adapt a platform. Yet voter turnout was the highest ever for a presidential election as 80 percent of the electorate cast a ballot.