| Time | Date | Name | Meet |
|---|---|---|---|
| 45.97 | Feb. 18, 2023 | Ethan Lowder | CCIW Championships |
| 46.01 | Feb. 13, 2016 | Victor Lugg | College Conference of Illinois & Wisconsin Championships |
| 46.11 | Feb. 16, 2013 | Victor Lugg | College Conference of Illinois & Wisconsin Championships |
| 47.18 | Feb. 12, 2005 | Justin Gorson | CCIW Championships |
| 49.34 | Feb. 15, 2003 | Jeff Horvath | CCIW Swimming Championships |
| 49.97 | Feb. 16, 2002 | Jeff Horvath | CCIW Championships |
