- 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.
- 2020s. In response to the COVID-19 pandemic, Tax School moved to an online-only delivery method for Fall Tax School and other events. Due to the overwhelming positive response and documented changes in attendees’ learning method preferences, more frequent webinars are added to the schedule each year, and 2-day Fall Tax School continues to be attended almost completely online. In February 2025, Tax School relocated its offices to the University of Illinois’ historic Taft House, located at 1401 S. Maryland Dr. in Urbana.