When Jefferson became President, he did several things. One of the first things he did was stop the delivery of the commissions to those who hadn’t yet received their commissions from the Midnight Appointments. John Adams had appointed many people to the federal judiciary just before his term ended. Some of these appointees didn’t have their paperwork or commissions completed before Thomas Jefferson became President. Since Jefferson was a Democratic-Republican and many of the appointees were Federalists, Jefferson ordered his Secretary of State, James Madison, to not deliver those commissions that hadn’t been finished before he took office. This action led to the famous Marbury v Madison court case.
Other actions that Jefferson took were to try to reverse some unpopular laws passed by the Federalists. The controversial Alien and Sedition Acts were ended. Taxes were reduced, including the unpopular Whiskey Tax. Jefferson wanted a smaller federal government. By cutting taxes, it allowed the government to have fewer federal workers. Jefferson completed many actions in the beginning of his presidency.