But his career as a correction officer at the Rockville County Correctional Facility was short-lived, according to Doug Garrison, a spokesman for the Indiana Department of Correction.
"[Kazmierczak] was employed, starting the 24th of September 2007, as a correction officer at the Rockville Correctional Facility," Garrison told ABCNEWS.com. "He left employment on the 9th of October 2007."
"He just did not come back to work," said Garrison.
Kazmierczak's sister, Susan, posted a statement on the door of her Urbana, Ill., home that said: "We are both shocked and saddened. In addition to the loss of innocent lives, Steven was a member of our family. We are grieving his loss as well as the loss of life resulting from his actions."
"Steve was the most gentle, quiet guy in the world. ... He had a passion for helping people," said Jim Thomas, an emeritus professor of sociology and criminology at Northern Illinois who taught Kazmierczak, promoted him to a teacher's aide and became his friend.
"He was very intelligent, brilliant really," said Alexandra Chapman, a graduate student at NIU who tutored with Kazmierczak and knew him well.
On a music site message board from 2006, posters who claimed to be his co-workers wrote, "I remember Steve Kazmierczak … the kind of person who injured kids on the train ride cuz he was mental and he shouldn't be given domain over kids on little faux-train cars with an aluminum baseball bat … "
Police Chief Grady said that those who knew him "revered him as an outstanding student" and had no inclination that Kazmierczak was capable of such carnage.
"I just want people to know he didn't fit the profile. He did a very terrible thing and there is no way we could have foreseen that at all," said Chapman.
Kazmierczak had served as a member of the NIU Academic Criminal Justice Association, was a teaching aid during his undergraduate years and in 2006 even received a Dean's Award from the sociology department.
In 2006, Kazmierczak was a co-author of an essay entitled "Self-Injury in Correctional Settings: 'Pathology' of Prisons or of Prisoners," in which an attached biography described him as having just begun his graduate work at NIU.
Kazmierczak's interests are listed as corrections, political violence and peace and social justice, according to the essay, and he had plans to co-author a manuscript on the role of religion in the formation of early prisons.
In another biography, apparently written by Kazmierczak for the Academic Criminal Justice Association's Web site, he pledged his commitment to social justice and his academic work.
"I've worked very hard as a student," the entry reads.
"It was very difficult and overwhelming to hear the news," said Jan Carter-Black, an associate professor of sociology, who was both Kazmierczak's professor and adviser at the School of Social Work at the University of Illinois. "I found Stephen to be a very committed student -- extremely respectful of me. I enjoyed having him as a student."
Kazmierczak was a student of Carter-Black's for about a month in the fall of 2007, when he was enrolled in a class called Human Behavior and the Social Environment.