Ann Lousin earned a law degree from the University of Chicago in 1968, and the following year worked as a research assistant for Illinois's Constitutional Convention, a subject that has fascinated her ever since. She has written extensively on the subject, and is regarded as the premier authority on ConCon. In 1970 Lousin was selected to serve first as a staff assistant and later as the parliamentarian in the Illinois House of Representations at a time when W. Robert Blair (Republican) was the Speaker of the House. In 1975, she began a long and distinguished career as professor at the John Marshall Law School. Governor Jim Thompson selected Lousin to chair the Civil Service Commission, a position she held until 1983.