Who was Thomas Jefferson and why was he important?

Thomas Jefferson (1743-1826), author of the Declaration of Independence and the third U.S. president, was a leading figure in America's early development. During the American Revolutionary War (1775-83), Jefferson served in the Virginia legislature and the Continental Congress and was governor of Virginia. Hope this helps! :)

Thomas Jefferson was the primary draftsman of the Declaration of Independence of the United States and the nation's first secretary of state (1789–94), its second vice president (1797–1801), and, as the third president (1801–09), the statesman responsible for the Louisiana Purchase.

Explanation:

Thomas Jefferson was the primary draftsman of the U.S. Declaration of Independence, the nation's first secretary of state and the second vice president (under John Adams). ... He was responsible for doubling the size of the United States by successfully brokering the Louisiana Purchase. Thomas Jefferson (1743-1826), author of the Declaration of Independence and the third U.S. president, was a leading figure in America's early development. During the American Revolutionary War (1775-83), Jefferson served in the Virginia legislature and the Continental Congress and was governor of Virginia. He later served as U.S. minister to France and U.S. secretary of state, and was vice president under John Adams (1735-1826). Jefferson, a Democratic-Republican who thought the national government should have a limited role in citizens’ lives, was elected president in 1800. During his two terms in office (1801-1809), the U.S. purchased the Louisiana Territory and Lewis and Clark explored the vast new acquisition. Although Jefferson promoted individual liberty, he was also a slave owner. After leaving office, he retired to his Virginia plantation, Monticello, and helped found the University of Virginia.