Transcript for Atlanta School Shooting Hero Was 'Prepared for a Purpose'
The incredible and inspiring Antoinette is the woman who saved an Atlanta school from becoming another columbine. Remember that. Back with us this morning, has a beautiful new book called "Prepared for a purpose." The inspiring woman of how one woman saved a school under siege. She'll join us live in a moment. Take a look back at the day -- I know show doesn't like this word but she became a hero. A lone gunman terrorized an Atlanta area elementary school. He just went outside and started shooting. Reporter: Firing an ak-47 in the front office carrying 500 rounds of ammunition. I can help you. Let me talk to them and let's see if we can work it out. Reporter: Face to face with potential tragedy school bookkeeper Antoinette tuff persuaded him to put down the weapon. It's going to be all right. Reporter: She promised he would be okay if he surrendered. I told him since he didn't hurt anyone that I would stay there with him until they came and that it was going to be okay. That we were going to get out safely. Reporter: When he put his gun down police swarmed. They're coming so just hold on, Michael. Go ahead and lay down. Stay on the ground. I have never been scared in all the days of my life. My goodness, welcome Antoinette tuff to "Good morning America." Wow, every time. Thank you. I'm telling you, about halfway through this book, it is so beautiful how you're weaving what happened last year with your own life. Why did you decide to do it like that? Because I wanted people to get the foundation of what was actually going on, not just the story, to go right back to the beginning. Was it difficult, though, to relive that day, what happened last August? Yes, but I know that the story needed to be told? And you are able to tell it and did it make you emotional, though, when you were reliving it? Did you have to take some breaks? Yeah, I did. I had an excellent person who actually wrote it for me which was actually Alex and Alex was a great writer and so even with the emotions behind it he helped to actually get me to pull out everything that we need to have done in the book. You went right back to work. Life could not have been business as usual, was it? No, it's not. How has it changed? It's changed a whole lot. I'm actually now I'm being a messenger for god and going out and do what god wants me to do. People, when they say you're a hero you're always like, no, how would you describe yourself? One of god's vessels. Just going out today to make insure that I do his work and do his will. You said when you were confronting this young man you were having a conversation with god. I was. I was just sitting there, you know, because I've actually talked to god and have a communication with him every monk it was just like normally just talking with like, okay, god, what am I going to do now? What do we have, you know, to make sure he was not agitated at all. And the way you were able to do it, trained professional said they could not have done it any better in talking to this young man and I -- can you just explain to us again and you wrote about it so beautifully about what that moment was like and how you heard a voice that told you what to do. Basically I said, okay, god, okay, okay, tell me what to do, how to do it because, remember now I was terrified on the inside. Sure. You got this gentleman who is -- he's already telling you everybody is going to die and you see it in his -- see it in his eye, see it in his movements so when you look at it you're like, okay, make sure you don't say the wrong word many make sure you say the right word so everybody at the end can get out alive including him. He felt that also. You really did care about him and now people are really showering you, oh, I saw that great commercial and you even had a chance to speak and later meet with the president of the United States. Yes, I did. President Obama. Awesome, awesome, awesome. Wonderful man, wonderful man. And how is it shooting this and being labeled and being called a hero? It was -- you know, you look at it and you know that in all reality you're really not a hero. I don't look at myself as a hero I look at, okay, god, what do you want me to do next? And that is a nonprofit organization. That's what he has you to do next. Tell us about that. I have a nonprofit which is called kids on the move for success and it actually started out with a goal, we have a board and my son is the vice president of my nonprofit so we're now actually going forth to carry out to help underprivileged students in education. Talk about your son. He is special. He's awesome. That's my baby. You sit back and look at children, you know, as parents we want a perfect child and, you know, you want all this but god gives you somebody that you look back and say, that's a blessing. He is a brave young man like his momma. Blessing. Antoinette, good to see you again. We were hanging out in Dallas with pat smith of the overcomers and you are definitely an overcomer. See you on "The view" a little bit later. Thank you.
This transcript has been automatically generated and may not be 100% accurate.