Author of the Declaration of Independence and the Statute of Virginia for Religious Freedom, third president of the United States, and founder of the University of Virginia.

He was considered an expert in many areas: architecture, civil engineering, geography, mathematics, ethnology, anthropology, mechanics, and the sciences.
Jefferson's greed for knowledge was insatiable, and he eagerly seized all means of obtaining it. It was his habit in discourse with all classes, the laborer as well as the man of science, to turn the conversation upon that subject with which his companion was best acquainted, whether it was farming, shoemaking, anatomy, astronomy, or fossils. Having drawn all the information his companion possessed, he noted it down in his memorandum book for future reference.

JFK told an assembly of U.S. Nobel Prize winners: "I think this is the most extraordinary collection of talent, of human knowledge, that has ever been gathered together at the White House -- with the possible exception of when Thomas Jefferson dined alone."

His father Peter Jefferson was a successful planter and surveyor and his mother Jane Randolph a member of one of Virginia's most distinguished families.

Continental Congress:
Having attended the College of William and Mary, Jefferson practiced law and served in local government as a magistrate, county lieutenant, and member of the House of Burgesses in his early professional life. As a member of the Continental Congress, he was chosen in 1776 to draft the Declaration of Independence, which has been regarded ever since as a charter of American and universal liberties.

Governor of Virginia:
After Jefferson left Congress in 1776, he returned to Virginia and served in the legislature and was elected governor from 1779 to 1781.

In 1784, he entered public service again, in France, first as trade commissioner and then as Benjamin Franklin's successor as minister. During this period, he avidly studied European culture, sending home to Monticello, books, seeds and plants, statues and architectural drawings, scientific instruments, and information.

Secretary of State - VP - 1790:
In 1790 he accepted the post of secretary of state under his friend George Washington. His tenure was marked by his opposition to the pro-British policies of Alexander Hamilton. In 1796, as the presidential candidate of the Democratic Republicans, he became vice-president after losing to John Adams by three electoral votes.

President - 1800:
Four years later, he defeated Adams and became president. Perhaps the most notable achievements of his first term were the purchase of the Louisiana Territory in 1803 and his support of the Lewis and Clark expedition.

Private Life after Public Service
Founded the University of Virginia:

Source: Brief Biography of Thomas Jefferson " Thomas Jefferson's Monticello

Inventor:
An inventor and gadgeteer of great ingenuity, Jefferson's practical innovations or improvements on others inventions included: the swivel chair, the polygraph, letter press, hemp break. pedometer, mouldboard plow, sulky, folding chair, dumb-waiter, double acting doors, a seven day clock, and a wind vane on the eastern portico of Monticello that enabled him to see which way the wind was blowing on a raining day without getting wet.
See about.com, storis63, UVA, EarlyAmerica.com

Scientist:

In Notes Jefferson writes at length on his native state's agriculture. This was not unusual for Jefferson since he felt that America had been designed by the Creator to be an agricultural country.
Throughout his life Jefferson experimented in agriculture with studies in crop rotation, soil cultivation, animal breeding, pest control, agricultural implements and improvement of seeds.
Source Thomas Jefferson, Scientist at EarlyAmerica.com

Quotes:

• "The God who gave us life, gave us liberty at the same time."
• "Under the law of nature, all men are born free, every one comes into the world with a right to his own person, which includes the liberty of moving and using it at his own. This is what is called personal liberty, and is given him by the author of nature, because necessary for his own sustenance."
• "We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty, and the pursuit of Happiness."
  Unfortunately, Thomas Jefferson himself never explained his use of the phrase "pursuit of happiness" in the Declaration of Independence.
• "Cultivators of the earth are the most virtuous and independent citizens."
• "I have lived temperately, eating little animal food, and that not as an aliment, so much as a condiment for the vegetables which constitute my principal diet."
• "The rights of conscience we never submitted, we could not submit. We are answerable for them to our God. The legitimate powers of government extend to such acts only as are injurious to others. But it does me no injury for my neighbour to say there are twenty gods, or no god. It neither picks my pocket nor breaks my leg. ... Reason and free enquiry are the only effectual agents against error."
• Were we directed from Washington when to sow, and when to reap, we should soon want bread.
• I sincerely believe that banking establishments are more dangerous than standing armies, and that the principles of spending money to be paid by posterity, under the name of funding, is but swindling futurity on a large scale.
• I hope we shall take warning from the example of England and crush in its birth the aristocracy of our moneyed corporations which dare already to challenge our Government to trial, and bid defiance to the laws of our country.
• Peace, commerce, and honest friendship, with all nations; entangling alliances with none.
• It is as useless to argue with those who have renounced the use of reason as to administer medication to the dead.
• Nothing is more certainly written in the book of fate than that these people are to be free; nor is it less certain that the two races equally free, cannot live in the same government. Nature, habit, opinion have drawn indelible lines of distinction between them.
• Let us in education dream of an aristocracy of achievement arising out of a democracy of opportunity.
• "Question with boldness even the existence of a god; because, if there be one, he must more approve the homage of reason, than that of blindfolded fear."
• He writes to William Short on October 31, 1819, he was convinced that the fragmentary teachings of Jesus constituted the "outlines of a system of the most sublime morality which has ever fallen from the lips of man."