But all that began to unravel last year when it was discovered that his past involved a heinous crime. Just how far is society willing to go to reintegrate that exploding population of ex-cons? Correspondent Vicki Mabrey reports.
If you passed Professor Paul Krueger on campus, you probably wouldn't give him a second glance. That's because he looks like the typical college professor.
For 15 years, Krueger taught education and business courses, most recently at Penn State University. He earned the respect of students and colleagues. But unbeknownst to anyone on campus, the respected professor was on parole for a triple murder he'd committed nearly 40 years ago.
It was a crime so horrific that it was considered one of the worst in Texas history. Even now, Krueger can't or won't talk about many of the details of that night. But he says it all started when he ran away to escape an abusive father in April of 1965.
"My real thing was getting away from my father and getting away from a real traumatic situation," recalls Krueger. "I was 17. I thought maybe I was old enough to go off on my own. And so I left."
Krueger, who had recently left military school, ran away from his California home with a friend. He had reportedly packed a cache of weapons. The teenagers ended up off the coast of Texas, where they came across three family men on a fishing trip. With his friend looking on, Krueger pulled out a gun. Then, without warning, he started shooting.
"There's one thing that I recall of that night rather clearly. And it's burned in my brain. We both said, 'This is a military operation.' And it was very consistent with our supposed training," says Krueger.
"Now, that sounds bizarre. You have to realize that you had two very disturbed kids. And they were looking for some kind of something, I don't know what, to hang their hats on. To somehow find a life."
Krueger reportedly unloaded one gun. Then, he grabbed another and continued firing. The bodies were so bullet-ridden that the autopsy couldn't determine how many times the men had been shot. Krueger says he didn't hate the men, and that they did nothing to hurt him. So why did he do it?
"I see these two children at that time. And I'm talking about myself, and there was this unemotional person that was devoid of feeling, saying it was a military operation. But then, the realization of what happened came through," says Krueger.
"It's been with me -- forever. I've tried to deal with this as an adult. I really have. And I feel that I could never atone for something like this."
Krueger was facing the death penalty, but because the victims' widows didn't press for it, he received three life sentences instead. Behind bars in Huntsville, Texas, the triple murderer began what he calls his transformation. And he eventually earned a bachelor's degree through a program that brought professors into prison.
"They not only valued my education, but in spite of my circumstances of being incarcerated, they valued me as a person, if that's hard to believe," says Krueger. "But they really did. And I believe that in my heart of hearts. And that motivated me to change."
But has it been a complete change? "I'm not the person of 40 years ago," says Krueger.
Could he snap and kill someone again? "No," he says. "Not with what I've had to live through."
Krueger was considered such a model prisoner that a Texas parole official eventually wrote in his file: "There is nothing further he could do to rehabilitate himself."
So despite the fact that he had murdered three men in cold blood, Krueger was released after only 12-and-a-half years in prison. While on lifetime parole, he went on to get three graduate degrees, get married, have a son and reinvent himself as a college professor.
Did his employers ever ask about his past – if he had ever been arrested or convicted of a crime?
"They didn't ask at Penn State, and I didn't tell," says Krueger, who began teaching there in 1999. In March 2003, his secret past caught up with him.
Pennsylvania learned that he was on parole from Texas because of a change in the policies governing parolees. Word of his murderous past soon became front-page news, and a job offer he'd just accepted from a national university in California was rescinded.
The next day, Penn State announced that he had resigned, and officials from both universities declined to be interviewed. But Penn State at the time released a statement saying, "His ability to carry out his responsibilities effectively…has been compromised in light of revelations about his history."
The families of the victims also refused to talk with 60 Minutes on camera. But while the widows had helped spare him from the death penalty, other family members now say they're angry not only over Krueger's teaching career, but that he'd been released from prison at all.
Back on campus, many of his former students, including Noela Haughton, Brian Lee and Bobby Jeter, rallied to his defense.
"If someone said to you, there is a murderer among you, he would be the last person on my mind," says Haughton.
"He is a wonderful professor and I think every day he's not in the classroom, we're losing again as a society," adds Lee.
But did the fact that Krueger committed these murders in cold-blood change their opinions? "He served his time for that. He paid his debt to society," says Jeter. "If we're to believe in our criminal-justice system, how can you continue to penalize him for that?"
But Pennsylvania State Rep. Matt Baker was so outraged that a triple murderer was on staff at Penn State that he proposed a law requiring all Pennsylvania universities to conduct criminal background checks before hiring professors.
"I think safety has to come first and foremost," says Baker. "When one thinks about attending college, I think the last thing that goes through their minds is that their professor might have committed a heinous crime of murder, let alone a triple murder."
Krueger, who has been out of prison for more than 25 years, has been a law-abiding citizen. Is there any reason to be concerned about student safety? And is it fair to penalize him for something that he's already served time for?
"A convicted triple murderer would be viewed as perhaps too great a risk," says Baker. "Some people would think that he should have gotten the death sentence. Some people believe he perhaps should have at least gotten a life sentence. Certainly not just 12-and-a-half years for three murders of innocent people. So, I personally don't believe he should be in a public position of authority and of trust."
Just how much authority and trust society is willing to grant ex-cons is the question. Some states have banned them not just from sensitive positions like working in nursery schools or law enforcement, but also from licensed professions, such as barbers or landscape architects.
Bryan Collier, head of the Texas parole division, oversees Krueger's parole and that of 77,000 other ex-convicts. Are there certain jobs that society is not yet ready to have parolees in?
"I definitely think so. I'm not sure that if you commit a crime of that nature, that limiting your ability of what you can achieve may be part of the process of paying for that crime," says Collier. "I'm not sure that that's wrong."
Does he think that society truly believes in rehabilitation? "I'd like to think so," says Collier. "But I would say there are definitely areas where none of us feel comfortable with someone who is either on parole, has a conviction. It still raises an area of concern for all of us."
Over the past year, Krueger has been unsuccessfully applying for teaching jobs. Does he think he deserves the same opportunities as those who haven't committed murder?
"Given the person that I am today, yes," says Krueger. "I think I bring value into the classroom."
But why should he get a second chance?"
"I would ask those people if they would please tell me what more that I need to do," says Krueger. "Is there anything that I could do to further atone? And I'll try, honest."