He was born and raised in Ingolstadt, where he attained the rank of Professor of Canon Law in 1772. Though educated by Jesuits and for a time a member of their order, his appointment as Professor of Natural and Canon Law at the University of Ingoldstadt in 1775 offended them. He broke with them and became increasingly liberal in his religious and political views, favoring deism and republicanism.
With the help of Baron Adolph von Knigge, on May 1, 1776 Weishaupt formed the Order of Perfectibilists, which was later known as the Illuminati. They declared its mission to be the development of morality and virtue and the creation of an association of good men to oppose the progress of evil. The actual character of the society was determined by an elaborate network of spies and counter-spies created to ensure virtue.
Weishaupt was initiated into Freemasonry Lodge "Theodor zum guten Rath", at Munich in 1777. He began working towards incorporating his system of Illuminism into that of Masonry, with the aim of spreading his ideals throughout the world.
After the society was banned by Bavaria's government in 1784, Weishaupt lost his position at the University of Ingolstadt and fled Bavaria. He received the assistance of Duke Ernest of Gotha, and lived in Gotha writing a series of works on Illuminism, including A Complete History of the Persecutions of the Illuminati in Bavaria (1785), A Picture of Illuminism (1786), An Apology for the Illuminati (1786), and An Improved System of Illuminism (1787). He died there in 1811, though some sources place the year of his death at 1830.
As Weishaupt lived under the tyranny of a despot and priests, he knew that caution was necessary even in spreading information, and the principles of pure morality. This has given an air of mystery to his views, was the foundation of his banishment.... If Weishaupt had written here, where no secrecy is necessary in our endeavors to render men wise and virtuous, he would not have thought of any secret machinery for that purpose. --Thomas Jefferson
A human devil. --Abbe Augustin Barruel