- 1940. First schools in DeKalb and Springfield.
- 1940s. Enrollees mostly farmers doing their own returns.
- 1950s. Enrollees include tax practitioners; IRS agents begin to help with instruction.
- 1960s. Schools more oriented to tax practitioners; Workbooks and other references provided annually.
- 1969. Illinois state income tax law enacted; State Department of Revenue joins program.
- 1970s. Attendance grew from just under 2,000 to approximately 4,000 enrollees. Basic Income Tax Preparation telenet courses were offered for the first time.
- 1980s. Attendance grew from 4,000 to over 5,300 enrollees. Number of schools offered grew to 26. An estimated 1 million federal and .75 million state tax returns were prepared by enrollees. Specialized seminars on S-Corporations and Small Business Issues were held.
- 1990s. Attendance grew from approximately 5,400 to over 6,200 enrollees. The number of schools grew to 31. Satellite programs were introduced in 1994 and expanded to video-Telnet programs in 1997 and 1998, serving more than 1,700 participants.
- 2000s. Attendance remains steady at approximately 6,000 participants. Summer seminars which cover in-depth participant-requested topics were initiated in 2001. The name of the program changed from Farm Income Tax School to University of Illinois Tax School in 2003. Webinars were introduced as a delivery method for instruction in 2008. Tax School becomes accredited by NASBA and the IRS, and additionally provides CPE credits for attorneys and insurance agents.
- 2010s. Fall Tax School adjusts to changes in how tax professionals obtain their CPE by adding more webinars to their offerings and initiating online self-study courses. The 2-day Fall Tax School and in-depth seminars continue to offer CPE to approximately 6,000 tax professionals annually.