Who were the leaders and constituents of the Whig and Democratic parties?

The Democratic Party was born in 1828 as the result of internal divisions in the Democratic-Republican Party. This division occurred because of disagreement over who would succeed President James Monroe. Early on, Andrew Jackson and Martin Van Buren were recognized as the leaders of this party. They strongly supported and advocated for Thomas Jefferson's vision of a decentralized agrarian society. The party was suspicious and sometimes outright hostile towards the power of the Federal government. Given the populist message of the party, their constituents tended to be farmers, frontiersmen, artisans, and the so-called "common man."
The Whig Party was born in response to Jackson's rise. It started as an amalgamation of the National Republican Party, the Anti-Masonic Party, and former Democratic-Republicans who disagreed with Jackson and Van Buren. Henry Clay emerged as an early leader of the nascent Whig Party. Daniel Webster, Truman Smith, John Crittenden, and William Seward were other early Whig leaders. It was their inability to agree on a single leader that allowed Jackson's successor, Van Buren, to take the presidency in 1837. The Whigs advocated for an interventionist approach to managing the economy of the United States. Their constituents tended to be leaders of corporations, banks, the wealthy elite, and supporters of a strong and active federal government. They tended to be more popular in cities than in rural areas. They also found support among evangelicals and abolitionists.
http://m.government-and-constitution.org/history-us-political-parties/whig-party.htm

Andrew Jackson was the leader of the Democratic Party. After the Era of Good Feelings had ended, Andrew Jackson was furious how the results of the election of 1824 unfolded. He believed he had the election stolen from him as a result of the “corrupt bargain” made between Henry Clay and John Quincy Adams. After this election, Andrew Jackson worked tirelessly to get nominated by the Democratic Party in 1828, which had formerly been known as the Democratic-Republican Party. Andrew Jackson worked to promote the interests of the common people and railed against actions taken by the Bank of the United States. After getting the nomination from the Democratic Party and winning the presidential election in 1828, Andrew Jackson successfully worked to prevent the bank’s charter from being renewed. He favored states’ rights over the power of the federal government and had support from common people such as farmers, laborers, and individuals living on the frontier.
The Whig Party, led by Henry Clay, Daniel Webster, and William Henry Harrison, believed the federal government should have an active role in the economy. When the economy declined after the election of 1836, the Whig Party favored an active government role to help bring the economic slide to an end. This was in contrast to the Democrats who believed in a laissez-faire, or hands-off, policy. When the Whig Party first formed, it had strong support from businesses and the financial industry. This party believed a national bank was essential to the economic success of the country. By 1840, the Whig Party also began to attract support from the common man. The Log Cabin Campaign was designed to help the Whig Party, particularly William Henry Harrison, get support from farmers and workers living in the West. William Henry Harrison won the election of 1840 and became President of the United States.

The Whig and Democratic Parties were two parties that ushered in the end of the Era of Good Feelings.
This version of the Democratic Party was born in 1828 when Andrew Jackson ran a campaign for the presidency speaking out against the alleged elitist Northeastern interests that backed the incumbent John Quincy Adams. Jackson won by courting the vote of the common man through means such as parades and barbecues. Jackson's domestic policies were marked by limited government; he was against infrastructure projects, which he thought were pork barrel projects for individual congressmen. He also failed to renew the charter for the Bank of the United States, leading to a financial panic which doomed his handpicked successor Martin van Buren in 1837. Jackson believed in the power of the veto, and his detractors often depicted him as a king; the Whig party was born out of a hatred of Andrew Jackson.
The leader of this party was Henry Clay, who believed that infrastructure improvements, a strong national bank, and larger tariffs on foreign goods would make the United States less dependent on European goods. The party started by Clay would also have common man appeal as its presidential candidate in 1840, William Henry Harrison, ran a campaign that depicted him as a common farmer when he was actually one of the richest men in Ohio. Whigs garnered support in the north Midwest, while Democrats largely controlled the South, especially after many expansionist Southerners backed the Democratic candidate for president James K. Polk. The Whig Party would ultimately split over the issue of slavery, with "conscience Whigs" having difficulty backing the slave owner Henry Clay. Many from the Whig party such as Abraham Lincoln and William Seward would go on to become the early stars of the Republican Party, which ran on a platform that included stopping the spread of slavery into the Western territories.