Final answer:
Andrew Jackson became the 7th president by winning the 1828 election and founded the Democratic Party, which championed the will of the majority and opposed a national bank.
Step-by-step explanation:
Andrew Jackson became America's 7th president following his victory in the election of 1828. Capitalizing on the expanding wave of democracy and leveraging his appeal as a champion of the common people, Jackson secured a dramatic win against John Quincy Adams. He achieved 56 percent of the popular vote and 68 percent of the electoral vote. Jackson and his supporters founded the Democratic Party, embracing ideals that promoted the interests and will of the majority, westward expansion, and opposition to a national bank, thus setting the foundations for the second party system in American politics.