The following is a script from "The Spy Among Us" which aired on May 10, 2015. Steve Kroft is the correspondent. Draggan Mihailovich, producer.

Tonight, we're going to tell you a story you've probably never heard before because only a few people outside the FBI know anything about it. It's a spy story unlike any other and if you think your life is complicated, wait till you hear about Jack Barsky's, who led three of them simultaneously. One as a husband and father, two as a computer programmer and administrator at some top American corporations and three as a KGB agent spying on America during the last decade of the Cold War.

The FBI did finally apprehend him in Pennsylvania but it was long after the Soviet Union had crumbled. What makes Jack Barsky's story even more remarkable is he's never spent a night in jail, the Russians declared him dead a long time ago, he's living a quiet life in upstate New York and has worked in important and sensitive jobs. He's now free to tell his story...as honestly as a former spy ever can.

Jack Barsky CBS News

Steve Kroft: So who are you?

Jack Barsky: Who am I? That depends when the question is asked. Right now, I'm Jack Barsky. I work in the United States. I'm a U.S. citizen. But it wasn't always the case.

Steve Kroft: How many different identities do you have?

Jack Barsky: I have two main identities. A German one, and an American one.

"Who am I? That depends when the question is asked. Right now, I'm Jack Barsky. I work in the United States. I'm a U.S. citizen. But it wasn't always the case."

Steve Kroft: What's your real name?

Jack Barsky: My real name is Jack Barsky.

Steve Kroft: And what name were you born with?

Jack Barsky: Albrecht Dittrich. Say that three times real fast.

Steve Kroft: Just say it once slowly...(laughs)

Jack Barsky: Albrecht Dittrich.

How Albrecht Dittrich became Jack Barsky is one of the untold stories of the Cold War, an era when the real battles were often fought between the CIA and the KGB. Barsky was a rarity, a Soviet spy who posed as an American and became enmeshed in American society. For the 10 years he was operational for the KGB, no one in this country knew his real story, not even his family.

Steve Kroft: Did you think you were going to get away with this?

Jack Barsky: Yeah, otherwise I wouldn't have done it (laughs).

Young Jack Barsky

What Barsky did can be traced back to East Germany, back to the days when he was Albrecht Dittrich. A national scholar at a renowned university in Jena, Dittrich was on the fast track to becoming a chemistry professor, his dream job.

Jack Barsky: Didn't work out that way, because I was recruited by the KGB to do something a little more adventurous.

Steve Kroft: Spy?

Jack Barsky: We called it something different. We used a euphemism. I was going to be a "scout for peace."

Steve Kroft: A KGB "scout for peace"?

Jack Barsky: That is correct. The communist spies were the good guys. And the capitalist spies were the evil ones. So we didn't use the word spy.

He says his spying career began with a knock on his dorm room door one Saturday afternoon in 1970. A man introduced himself, claiming to be from a prominent optics company.

Jack Barsky: He wanted to talk with me about my career, which was highly unusual. I immediately, there was a flash in my head that said, "That's Stasi."

Steve Kroft: East German secret police?

Jack Barsky: East German secret police, yeah.

It was a Stasi agent. He invited Dittrich to this restaurant in Jena where a Russian KGB agent showed up and took over the conversation. The KGB liked Dittrich's potential because he was smart, his father was a member of the Communist party and he didn't have any relatives in the West. Dittrich liked the attention and the notion he might get to help the Soviets.

Steve Kroft: And what did you think of America?

Jack Barsky: It was the enemy. And, the reason that the Americans did so well was because they exploited all the third-world countries. That's what we were taught, and that's what we believed. We didn't know any better. I grew up in an area where you could not receive West German television. It was called the "Valley of the Clueless."

For the next couple of years, the KGB put Dittrich through elaborate tests and then in 1973 he was summoned to East Berlin, to this former Soviet military compound. The KGB, he says, wanted him to go undercover.

Jack Barsky: At that point, I had passed all the tests, so they wanted, they made me an offer.

Steve Kroft: But you had been thinking about it all along, hadn't you?

Jack Barsky: That's true. With one counterweight in that you didn't really know what was going to come. Is-- how do you test drive becoming another person?

It was a difficult decision, but he agreed to join the KGB and eventually found himself in Moscow, undergoing intensive training.

Jack Barsky: A very large part of the training was operational work. Determination as to whether you're being under surveillance. Morse code, short wave radio reception. I also learned how to do microdots. A microdot is, you know, you take a picture and make it so small with the use of microscope that you can put it under a postage stamp.

The Soviets were looking to send someone to the U.S. who could pose as an American. Dittrich showed a command of English and no trace of an East German accent that might give him away. He learned a hundred new English words every day.

Jack Barsky: It took me forever. I did probably a full year of phonetics training. The difference between "hot" and "hut." Right? That, that's very difficult and, and most Germans don't get that one.

Steve Kroft: Did you want to go to the United States?

Jack Barsky: Oh yeah. Sure. There was New York, there was San Francisco, you know, we heard about these places.

Steve Kroft: Your horizons were expanding...

Jack Barsky: Oh, absolutely. Now I'm really in the big league, right?

Dittrich needed an American identity. And one day a diplomat out of the Soviet embassy in Washington came across this tombstone just outside of D.C. with the name of a 10-year-old boy who had died in 1955. The name was Jack Philip Barsky.

Jack Barsky: And they said, "Guess what? We have a birth certificate. We're going to the U.S."

Steve Kroft: And that was the Jack Barsky birth certificate.

Jack Barsky: The Jack Barsky birth certificate that somebody had obtained and I was given. I didn't have to get this myself.

Steve Kroft: Did you feel strange walking around with this identity of a child?

Jack Barsky: No. No. When you do this kind of work, some things you don't think about. Because if you explore, you may find something you don't like.

The newly minted Jack Barsky landed in New York City in the fall of 1978, with a phony back story called a legend and a fake Canadian passport that he quickly discarded. The KGB's plan for him was fairly straightforward. They wanted the 29-year-old East German to get a real U.S. passport with his new name, then become a businessman, then insert himself into the upper echelons of American society and then to get close to National Security Adviser Zbigniew Brzezinski so that he could spy on him.

Jack Barsky: That was the plan. It failed.

Steve Kroft: Why?

Jack Barsky: Because I was not given very good instructions with regard to how to apply for a passport.

When he went to apply for a passport at Rockefeller Center, Barsky was thrown off by the list of questions.

Jack Barsky: Specific details about my past, for which I had no proof. So I walked out of it.

Steve Kroft: Did the KGB have a pretty good grasp on the United States and how things worked there?

Jack Barsky: No.

Steve Kroft: No?

Jack Barsky: Absolutely not. They made a number of mistakes in terms of giving me advice, what to do, what not to do. They just didn't know.

Left to fend for himself in a country the KGB didn't understand, he got himself a cheap apartment and tried to make do with a birth certificate and $6,000 dollars in cash the Soviets had given him. His spying career at that point more resembled the bumbling Boris Badenov than James Bond...

Steve Kroft: So you were working as a bike messenger?

Jack Barsky: Right.

Steve Kroft: That doesn't sound like a promising position for a spy.

Jack Barsky: No. But there were a lot of things that I didn't know...

Steve Kroft: So how close did you ever get to Brzezinski?

Jack Barsky: Not very.

To get a Social Security card, which he would need if he wanted a real job, Barsky knew he would have to do some acting.

Jack Barsky: It was unusual for a 30-plus-year-old person to, to say, "You know, I don't have a Social Security card. Give me one." So in order to make my story stick I made my face dirty. So I looked like somebody who just came off a farm. It worked! The lady asked me, she said, "So how come you don't, you don't have a card?" And when the answer was, "I didn't need one." "Why?" "Well, I worked on a farm." And that was the end of the interview.

The Social Security card enabled him to enroll at Baruch College in Manhattan, where he majored in computer systems. He was class valedictorian but you won't find a picture of him in the school yearbook. In 1984, he was hired as a programmer by Metropolitan Life Insurance where he had access to the personal information of millions of Americans.

Steve Kroft: You were writing computer code?

Jack Barsky: Right. Yes. Lots of it. And I was really good at it.

What he didn't write, he stole, on behalf of the KGB.

Steve Kroft: What was the most valuable piece of information you gave them?

Jack Barsky: I would say that was the computer code because it was a very prominent piece of industrial software still in use today.

Steve Kroft: This was IBM code?

Jack Barsky: No comment.

Steve Kroft: You don't want to say?

Jack Barsky: No. It was good stuff. Let's put it this way, yeah.

Steve Kroft: It was helpful to the Soviet Union...

Jack Barsky: It would've been helpful to the Soviet Union and their running organizations and, and factories and so forth.

Steve Kroft: How often did you communicate with the Russians?

Jack Barsky: I would get a radiogram once a week.

Steve Kroft: A radiogram, meaning?

Jack Barsky: A radiogram means a transmission that was on a certain frequency at a certain time.

Every Thursday night at 9:15 Barsky would tune into his shortwave radio at his apartment in Queens and listen for a transmission he believed came from Cuba.

Jack Barsky: All the messages were encrypted that they became digits. And the digits would be sent over as, in groups of five. And sometimes that took a good hour to just write it all down, and then another three hours to decipher.

During the 10 years he worked for the KGB, Barsky had a ready-made cover story.

Steve Kroft: When somebody'd ask you, you know, "Where you from Jack?," what'd you say?

Jack Barsky: I'm originally from New Jersey. I was born in Orange. That's it. American. Nobody ever questioned that. People would question my, "You have an accent." But my comeback was, "Yeah, my mother was German and we spoke a lot of German at home."

Steve Kroft: You had to tell a lot of lies.

Jack Barsky: Absolutely. I was living a lie.

Steve Kroft: Were you a good liar?

Jack Barsky: The best.

You had to be a good liar to juggle the multiple lives he was leading. Every two years while he was undercover for the KGB, Barsky would return to East Germany and Moscow for debriefings. During one of his visits to East Berlin he married his old girlfriend Gerlinde and they had a son.

Steve Kroft: Did that complicate matters?

Jack Barsky: Initially it wasn't complicated at all, it got complicated later.

Steve Kroft: Because?

Jack Barsky: Because I got married in the United States to somebody else.

Steve Kroft: Did she know about your other wife in Germany?

Jack Barsky: No.

Steve Kroft: Did your wife in Germany know about the...

Jack Barsky: Not at all.

Steve Kroft: So you had two wives?

Jack Barsky: I did. I'm, I was officially a bigamist. That's, that's the one thing I am so totally not proud of.

Steve Kroft: Being a spy was all right. Being a bigamist...

Jack Barsky: In hindsight, you know, I was a spy for the wrong people. But I, this one hurt because I had promised my German wife, that you know, we would be together forever. And I broke that promise. And the one way I can explain it to myself is I had separated the German, the Dittrich from the Barsky to the point where the two just didn't know about each other.

Not only did he have two different identities, and two wives, he had a son named Matthias in Germany and a daughter named Chelsea in America. And by November 1988, a radiogram from the KGB would force him to make an excruciating choice.

Jack Barsky: I received a radiogram that essentially said, "You need to come home. Your cover may soon be broken and you're in danger of being arrested by the American authorities."

Barsky was given urgent instructions from the KGB to locate an oil can that had been dropped next to a fallen tree just off this path on New York's Staten Island. A fake passport and cash that he needed to escape the United States and return to East Germany would be concealed inside the can.

Jack Barsky: I was supposed to pick up the container and go on, leave. Not even go back home to the apartment, just disappear. The container wasn't there. I don't know what I would have done if I had found it, but I know what I did when I didn't find it. I did not tell them, "repeat the operation." I made the decision to stay.

Steve Kroft: Why?

Jack Barsky: Because of Chelsea.

Steve Kroft: Your daughter.

Jack Barsky: Yes. If Chelsea's not in the mix, that's a no brainer, I'm outta here.

Barsky had chosen Chelsea over Matthias.

Jack Barsky: I had bonded with her. It was a tough one because on the one hand I had a wife and child in Germany but if I don't take care of Chelsea, she grows up in poverty.

Steve Kroft: This may be a little harsh but it sounds like the first time in your life that you thought about somebody besides yourself.

Jack Barsky: You're absolutely right. I was quite an egomaniac. I was.

Jack Barsky was still left with the not insignificant matter of telling the KGB that he was staying in America. In a moment, we'll tell you how he duped the KGB and how the FBI changed his life.

Part Two

At the end of 1988, Jack Barsky's 10-year run as a clandestine KGB agent in the United States was about to come to an end. He had ignored Soviet warnings that his cover had been blown and decided to remain in America and not return to his native East Germany. He was taking a chance that no one in America would ever find out who he really was. And he was taking a bigger chance that the KGB wouldn't retaliate for disobeying an order. The urgency with which the Soviets seemed to view the situation became clear one morning in Queens.

Jack Barsky says he was on his way to work in December 1988, standing and waiting for an "A" train on this subway platform when a stranger paid him a visit.

Jack Barsky: There's this character in, in a black coat and he sidles up to me and he whispers in my ear, he says, "You gotta come home or else you're dead." And then he walked out.

Steve Kroft: Russian accent?

Jack Barsky: Yes.

Steve Kroft: That's an incentive.

Jack Barsky: It's an incentive to go.

Steve Kroft: I mean spies get killed all the time.

Jack Barsky: They do. But not me. The entire time I always had this childlike belief that everything would be all right.

"There's this character in, in a black coat and he sidles up to me and he whispers in my ear, he says, 'You gotta come home or else you're dead.' And then he walked out."

Steve Kroft: So what are you going to tell the Russians?

Jack Barsky: Well, I (sighs) I sent them, this "Dear John" letter, the goodbye letter in which I stated that I had contracted AIDS and that the only way for me to get a treatment would be in the United States.

Steve Kroft: You just wrote them a letter and said, 'I can't come back. I've got AIDS"?

Jack Barsky: There's three things I tell people that the Russians were afraid of. AIDS, Jewish people and Ronald Reagan. And they were deathly...

Steve Kroft: In that order?

Jack Barsky: I think Ronald Reagan took the top spot. They thought he would push the button.

The AIDS letter apparently worked because in East Berlin the Soviets told his German wife Gerlinde he wasn't coming back.

Jack Barsky: They went to Gerlinde and told her that I had died of AIDS. So I think they just wrote me off completely.

Steve Kroft: You were officially dead in East Germany?

Jack Barsky: Right. After five years she was able to declare me dead.

Once the Berlin Wall fell and the Soviet Union fell apart, Barsky was a man without a country. No one would want him back. He felt his secret was safe in America. He became a family guy, with a wife, two kids, Chelsea and Jessie, and a job. He burrowed himself into suburbia, keeping a low profile.

Jack Barsky: I was settling down, I was living in the, in rural Pennsylvania at the time, in a nice house, with two children. I was, like, typical middle class existence.

And his life would have stayed quiet if a KGB archivist named Vasili Mitrokhin hadn't defected to the West in 1992 with a trove of notes on the Soviets' spying operations around the world. Buried deep in his papers was the last name of a secret agent the KGB had deployed somewhere in America: Barsky.

Joe Reilly: We were concerned that he might be running an agent operating in the federal government somewhere. Who knows? In the FBI, the CIA, the State Department. We had no idea.

Joe Reilly was an FBI agent when the bureau got the Mitrokhin tip, and the Barsky case quickly became serious enough that FBI director Louis Freeh got personally involved. The FBI didn't know who or where he was, but the best lead seemed to be a Jack Barsky who was working as an I.T. specialist in New Jersey, with a suburban home across the border in Mount Bethel, Pennsylvania.

Steve Kroft: Aside from his name was there anything else that made you suspicious and make you think that this was the guy you were looking for?

Joe Reilly: Yes. One thing was the fact that he had applied for a Social Security number late in life. Especially someone like him who was educated and intelligent.

The FBI began following Barsky, and when this surveillance photo caught him talking to a native of Cuba, the bureau grew increasingly concerned.

Joe Barsky: There were some indications that I could possibly be the head of a international spy ring, because I had a friend who was originally from Cuba. And it so happened that this friend owned an apartment that was rented to a Soviet diplomat. So that one and raised all kinds of flags and they investigated me very, very, very carefully.

FBI agent Joe Reilly went so far as to set up an observation post on a hillside behind Barsky's house. This is a picture he took of his view.

Joe Reilly: I got a telescope and binoculars, as if I was a birdwatcher. But I was looking at his backyard and at him. Over time, I learned a great deal about him.

Steve Kroft: Like what?

Joe Reilly: ...just watching him. Well, I became convinced that he loved his children. And that was important because I wanted to know if he would flee. There was less chance of that if, if he was devoted to his children. And he was.

But that wasn't enough for the FBI. The bureau bought the house next door to get a closer look at the Barskys.

Steve Kroft: Did you get a good deal?

Joe Reilly: I think we paid what he was asking. And we had agents living there so that we could be sure who was coming and going from his house without being too obvious in our surveillance.

Steve Kroft: You had no idea the FBI was living next door to you?

Jack Barsky: No.

Steve Kroft: Never saw...

Jack Barsky: No.

Steve Kroft: ...Joe Reilly up on the hill with the binoculars?

Jack Barsky: Absolutely not.

When the FBI finally got authorization from the Justice Department to bug Barsky's home, the case broke wide open.

Joe Reilly: Within, I'd say, the first two weeks that we had microphones in his house, he had an argument with his wife in the kitchen. And during the course of that dispute, he readily admitted that he was an agent, operating from the Soviet Union.

It was all the FBI needed to move in on Barsky. They set a trap for him at a toll bridge across the Delaware River as he drove home from work late one Friday afternoon in May of 1997.

Jack Barsky: I'm being waved to the side by a state trooper. And he said, "We're doing a routine traffic check. Would you please get out of the car?" I get out of the car and somebody steps up from, from behind and shows me a badge. And he said, "FBI. We would like to talk to you."

Joe Reilly: His face just dropped. And we told him that he had to go with us.

Jack Barsky: The first words out of my mouth were, "Am I under arrest?" And the answer was, "No." Now that took a big weight off of me, so I figured there was a chance to get out of this in one piece. And the next question I asked, "So what took you so long?"

The FBI had rented an entire wing of a motel off Interstate 80 in Pennsylvania for Barsky's interrogation.

Joe Reilly: But on the way to the motel, I remember turning to him. And I, I told him that this didn't have to be the worst day of his life. And he immediately realized that he had an out.

Jack Barsky: I said to them, "Listen, I know I have only one shot out of this and that means I need to come clean and be 100 percent honest and tell you everything I know."

The FBI questioned Barsky throughout the weekend and gave him a polygraph test that he passed. Convinced that his spying days were over, and that his friendship with the Cuban was just that, the FBI decided to keep the whole thing quiet and allowed Barsky to go back to work on Monday morning.

Steve Kroft: Was he charged with something?

Joe Reilly: No.

Steve Kroft: Even though he confessed to being a Soviet spy?

Joe Reilly: Yes.

Steve Kroft: That seems odd.

Joe Reilly: Well, we wanted him to cooperate with us. We didn't want to put him in jail. He was no use to us there.

Barsky continued to meet not only with the FBI but with the National Security Agency to offer his first-hand insights into the KGB and the Russians.

Jack Barsky: I was able to provide them with a lot of valuable information how the KGB operated.

The only people who were aware of his secret were the FBI and Penelope, his wife in America, who subsequently filed for divorce. His daughter Chelsea, then a teenager, knew only that he wanted to tell her something when she turned 18. That day finally arrived on a four-hour drive to St. Francis University.

Chelsea: He started chuckling to himself and he said, "Well, I'm a, I was a spy. I was a KGB spy." I was like "What? Really?"

Jack also revealed to Chelsea why he had decided to stay in America.

Chelsea: He said that, you know, he fell in love with me and my, my curls when I was a little baby. And then I cried.

Steve Kroft: Did he tell you everything?

Chelsea: No, he didn't. He didn't tell me 100 percent the whole truth. He left some things out at that point.

Jack Barsky: I told her everything that you can tell in four hours that is age appropriate. She was still a teenager. I may not have told her that I was married in Germany.

He waited another two years before he matter-of-factly dropped another bombshell about his past.

Chelsea: He just looked straight ahead at the TV. And he said, "Did I tell you you have a brother?" And I turned my head. I'm like, "What? Are you serious?"

The half brother was Matthias, the boy Jack had left behind in Germany. Chelsea was determined to find him. Jack didn't like the idea.

Jack Barsky: I did not feel comfortable getting in touch with him. I did not feel comfortable with my acknowledging my German past.

After a year of trying to track him down online, Chelsea finally got a reply from Matthias...

Chelsea: The subject line said, "Dear little sister." And when I saw, "Dear little sister," I just started weeping, because that meant everything to me. That meant that he accepted me.

Matthias: And this is me...

A month later, Matthias was in Pennsylvania visiting Chelsea and her brother Jessie. They hit it off. Matthias wasn't interested in seeing his father, then changed his mind.

Barsky's children, from left: Jessie, Matthias and Chelsea

Steve Kroft: Was it awkward?

Jack Barsky: I just remember he stared at me for a couple of minutes. He just stared at me.

Steve Kroft: I mean he had reason to be angry with you.

Jack Barsky: When I told him the dilemma that I was faced with, he actually said, "I understand."

Steve Kroft: And what's your relationship like with Matthias now?

Jack Barsky: He feels like he's my son.

Gerlinde, the wife in Germany who thought he was dead, wants nothing to do with Jack today - or with 60 Minutes.

He has remarried and has a four-year-old daughter. They live in upstate New York where Jack has worked as director of software development for a company that manages New York's high voltage power grid, a critical piece of U.S. infrastructure. When he told his employer recently that he had once been a KGB spy, he was placed on a paid leave of absence. Before becoming an American citizen last year, he had been given a clean bill of health by the FBI and U.S. intelligence agencies. But in the world of espionage it's often difficult to tell what's true and what's legend.

Steve Kroft: Are you telling the truth right now?

Jack Barsky: I am, absolutely. The truth as far as I know it. Yes.

Steve Kroft: As far as you know it?

Jack Barsky: Well, you know, sometimes memory fails you. But I am, I am absolutely not holding back anything.

Steve Kroft: Why tell the story now?

Jack Barsky: I want to meet my maker clean. I need to get clean with the past. I need to digest this fully.

The FBI agent who apprehended him, Joe Reilly, still believes in Barsky. And in yet another twist to this story, the two are good friends and golfing buddies.

Joe Reilly: He's a very honest person. And if you want to find out how honest someone is, play golf with them.

Steve Kroft: But you're a former FBI guy and he's a former spy. What's the bond?

Joe Reilly: It's personal. He credits me for keeping him out of prison.

After nearly 30 years, Jack Barsky went back to visit a unified Germany, first in October, then again last month.

[Jack Barsky: So that was essentially the very beginning of my career...]

He showed his kids where this improbable tale began and some other key settings in his odyssey. And he caught up with old classmates who knew him as Albrecht Dittrich.

Barsky in Germany with his American children CBS News

Steve Kroft: When you're here in Germany...

Jack Barsky: Yeah...

Steve Kroft: ...are you Albrecht or are you Jack?

Jack Barsky: No, I'm Jack. I am 100 percent Jack. You know, the, I let the Albrecht out and sometimes he interferes, but they, they get along very well now (laughs)...

The Berlin wall, which once divided east and west, is now gone except for a section that has been turned into an art display. Checkpoint Charlie, once the epicenter of the Cold War, is now a tourist attraction, full of kitsch. Statues of Karl Marx and Friedrich Engels still stand in the eastern part of Berlin, relics of another era as is the man who straddled two worlds and got away with it.