Thomas Jefferson was an American statesman, diplomat, lawyer, architect, philosopher, and Founding Father who served as the third president of the United States from 1801 to 1809. He had previously served as the second vice president of the United States under John Adams between 1797 and 1801. Thomas Jefferson, a spokesman for democracy, was an American Founding Father, the principal author of the Declaration of Independence (1776), and the third President of the United States (1801–1809). As the “silent member” of the Congress, Jefferson, at 33, drafted the Declaration of Independence. Surprising Facts About Thomas Jefferson 1. He was a (proto) archaeologist. Mastodon Mandible. 2. He was an architect. Detail of Jefferson's Floor Plan for Monticello. 3. He was a wine aficionado. Monticello's Wine Cellar. 4. He was a founding foodie. 5. He was obsessed with books.