Thomas Jefferson's Accomplishments Thomas Jefferson, author of the Declaration of Independence and third President of the United States, was the nation's greatest champion of representative democracy and the rights of man. He was a philosopher, educator, naturalist, politician, scientist, architect, inventor, musician, and writer. His interests were boundless, and his accomplishments were great and varied. Through his writings and speeches, he communicated his brilliant ideas of independence, democracy, and philosophy. Three of his most important accomplishments were the Declaration of Ind