Both his parents died when he was nine years old, after their vehicle collided with a truck; Wirsum escaped unhurt.
[4] Wirsum was a member of The Hairy Who (along with James Falconer, Art Green, Gladys Nilsson, Jim Nutt, and Suellen Rocca).
Wirsum later recounted how he felt that "they were staying too close to the initial point of inspiration", adding how he preferred "things that were more inventive".
[2] During the early 1970s, Wirsum taught at the Sacramento State College, the only time he resided outside of Chicago.
[3] Wirsum died of cardiac arrest on May 6, 2021, at Advocate Illinois Masonic Medical Center in Lake View, Chicago, at the age of 81.