Transcript for Making of a President Part 1: Donald Trump's New York City Childhood
Good evening. I'm Elizabeth vargas. And I'm David Muir. Millions of Americans are still talking about the election. It's a triumph for millions who feel they have finally been heard. And others asking how this could have happened. And late this week, that moment. The president and the president-elect. The first step on a long road toward healing. We're in unchartered political territory. Tens of thousands taking to the streets to protest, after one of the most divisive campaigns. How will this shape American history? Here's Tom llamas. Reporter: In 70 days Donald Trump will have a new job and a new home. Trading three floors of his glittering versailles-inspired penthouse for the slightly more staid corridors of the white house. I'm looking around this room. The white house might be a step down. The white house is the white house. It's is just a spectacular place, and it's something very special. Reporter: Lara trump is married to Donald's son Eric. Will they totally redecorate the white house to look like trump tower? They'll make things how they like them, comfortable but nice and well done and tasteful. They're not gonna be knocking down any walls. Reporter: So how did he get there? We're going to get to work immediately for the American people. Reporter: Even his close friends like billionaire real estate tycoon Richard lefrak never saw it coming. I'm not surprised. I'm astonished. I'm more than surprised. But he gets the ball down the field. He's gonna put it in the end zone and score a touchdown. That's the way he is. I love this country. Thank you. Thank you very much. Reporter: It's a story that begins about 15 miles away from his victory party, 70 years ago in Jamaica estates, a wealthy neighborhood in queens, new York. You can't understand Donald without looking at his childhood. Reporter: Donald J. Trump lived in this ornate home, the fourth of five children. He did not grow up as a middle-class kid. The family had chauffeurs. He was taken to school in a limousine. He never had to work regular jobs. Reporter: He described his mother Mary, a Scottish immigrant, as the perfect housewife. His father Fred was a millionaire real estate developer. The trump patriarch has been described as a human machine. Driven. His father was, you know, he was a demanding guy, and he did very much push Donald. Donald is some ways was the chosen son. Reporter: That ambition was was unmistakably prevalent in young Donald's DNA. Donald, I think, was more than a troublemaker. He was a profound brat. He has said that he punched his teachers when he didn't like what he was being told to do. Reporter: In need of discipline young Donald was shipped off to New York military academy. Once he came under the control of the staff at the school, he wanted to excel. He had to be first at everything, even if it was just first inline in the cafeteria. Reporter: Just last year trump told ABC's Barbara Walters about his dreams at that time in his life. What was your fantasy when you were very young? To be a baseball player. I was a great baseball player. What position? First base. Catcher, first base. But in those days you got paid $2, right? And that's not for Donald Trump? I mean, no. But I wanted to be a movie maker. Reporter: Do you think his father had any role in him not pursuing that career in show business? I think there was no way Donald wasn't inevitably going to become a real estate developer. He's still fascinated by stardom. I think that was one of things that stood out for me was this cinematic sense he has of himself. He identifies strongly with Orson wells in "Citizen Kane." But at the end of the day, his father exerted a pretty inescapable pull on him to come back to the family business. Reporter: He accompanied his father to sites all over new York's outer boroughs where Fred trump was building middle and low-income housing. And I started off making little deals in Brooklyn and queens with my father and they seemed to work out. Reporter: And then with a loan from dad, Donald Trump struck out on his own. I think the rules that Fred trump taught his son Donald began with, you must be a winner. He plays hard and wants to win. And if that means setting the rules himself, he'll set the rules himself and then try to get everyone else to play by them. Reporter: Those rules would have devastating consequences for Donald's brother Fred Jr. He drank heavily and died of heart failure at the age of 43. I think Fred would have been very happy if he didn't have to compete. He had to compete because of the environment, he had to compete and it ultimately ended up destroying him and it was very sad, very sad. And ultimately it was alcohol that just decimated him. And I'm glad I'm not a drinker. I've never has a drink in my life. Reporter: Younger brother Robert who worked for Donald later in life learned what older brother Donald was like at an early age. Robert had a set of blocks and I had a set of blocks and I asked Robert if I could have his blocks and I built a beautiful tall block building and then I said I like it so much that I glued it together and then Robert couldn't have his blocks. So I don't know, somehow that story is a story that a lot of people have asked me about, I don't know. What do you think it says? Well, it says I think that just even at a young age I wasn't so much different than I am now, I don't know. You had to get what you wanted even if it was somebody else's blocks. Well, that's the old story, isn't it, huh? Reporter: Richard lefrak has been friends with Donald Trump for nearly half a century. He says the man he knows is not that different from the boy gluing his brother's confiscated blocks. The drive, the determination, this kind of boundless energy that he has. That's always been Donald. He loves to accomplish things. And he loves to be complimented for his achievements. Reporter: His longtime staffer Lynne Patton says the Seri Twitter user is quite old-fashioned, at least when it comes to technology. It took us a while to wean him from a flip phone to smart phone. Trump runs things his way and it works for him. Don't fix it if it ain't broke. There is no such thing as an e-mail from Donald Trump. That does not exist. But he does take the time to write very nice handwritten notes. Donald never wants to curl up with a book. Donald likes activity. He likes people. What words would you use to describe Donald Trump? I've always had great imagination. I've had great success with money. I've actually gotten along well with people over the years. You have said that one of the most important aspects in your personality is winning. Why winning? What about the, "It's not whether you win or lose, it's how you play the game?" I like winning better. Look, we have to win. Reporter: Trump says another part of the formula for success is not revealing your weaknesses. What is your greatest fear? Well, I don't want to reveal fears because if I reveal fears, I'm giving up something. We all have certain fears and everybody has fears. But I don't like revealing my fears. My name is Donald Trump, and I'm the largest real estate developer in New York. Reporter: Next after extending his footprint on land, he conquered the air. Television. You wanna be in the presence of Donald J. Trump, you cannot be weak. You're fired.
This transcript has been automatically generated and may not be 100% accurate.