Transcript for 'Just Mercy' and the real-life story of the attorney who exonerated death row inmates
Montgomery, Alabama, where the demons of Dixie still stand on the lawn. The memorial was haunting, a dark truth one man thought America should see. I can't imagine creating something that may engage people. And yet here we are. Reporter: I walked with Bryan Stevenson through this copper canyon, a sobers space, dedicated to black men and women lynched in America. What do you want people to sense? I think it's the sense that this violence was lifted up over people. People don't know what it was like to live in a space where were you surrounded by such torture and terror and violence. And nobody did anything. Reporter: Stevenson views America's dark past as directly connected to what he sees as her trouble present. We have the highest rate of incarceration because we have allowed ourselves to be governed by fear and anger. It was the same fear and anger that allowed us to be involved in genocide and lynching. Reporter: Getting 135 people off death row. Data suggests that for every nine people executed, one has been exonerated. His life's work has been memorialized in a new film "Just mercy." We all need grace. We all need mercy. I hope from watching the movie and thinking more critically people will kind of see this issue the way I see it. I don't think the threshold question of the death penalty is do people deserve to die for the crimes they've committed, I think the threshold question is, do we deserve to kill? Reporter: It comes at an appropriate time. They will resume capital punishment at the federal level after nearly two decades. Actor Michael B. Jordan portrays Stevenson in the film. You a lawyer? Yes, ma'am. My name is Bryan Stevenson. Reporter: And academy award winner, Jamie Foxx, plays one of his first death row clients. Walter Mcmillen. All they can think of is I look like a man who could kill somebody. That's not what I think. Reporter: What inspired you to want to take this project on? Nobody's perfect, but he's really close. He's a much better person than I am. He's really beating the drum for justice, nonstop. Reporter: Walter Mcmillen, the character you play. The most important movie I ever do. Reporter: Really? When we talk about importance, I'm talking about the importance of the message. And when you go on your social media, and you're able to see a young black man being killed by a police officer, because it allows us to address those types of symptoms in an artistic way. Here's Walter Mcmillen. In a sense, wrongly convicted of a crime that, a city he'd never been in, a person he never met and all of a sudden he sits on death row. Reporter: Before his trial. Before his trial. The worst thing you can give a death row inmate is hope, and all of a sudden, hope walks in, in the form of Bryan Stevenson. You don't know what it is down there, you're guilty from the moment you're born. Reporter: When you say guilty from the moment you're born. I grew up in Texas. I was 8 years old and I got called By a grown man. How is me being born, how can I receive all of this hate? When Jamie plays Walter, I think he exposes the agony of being wrongly convicted and the Reporter: What do you think of Michael B. Jordan playing you. I'm honored. He was terrific. The only thing I asked him not to do is to go on some lawyer I said you can keep the creed body. It's to achieve justice. And as long as you keep fighting this, someone from your county has literally gotten away with murder. Reporter: Stevenson and his organization, the equal justice initiative, have dedicated themselves to changing the criminal justice system and people's lives. One of those lives changed, Anthony ray Hickman. You can say that you got an innocent man off death row. Reporter: We first met Hinton almost five years ago, just days after he was released from Alabama's death row where he had served 30 straight years for two murders he did not commit. Would you believe, this is the first time I've been in the rain in 30 years? It's, it feels wonderful. Yes, it feels wonderful. Reporter: But now, thanks to Stevenson, what's left of this life is all his. What's freedom taste like to a grown man? Ooh. Freedom tastes good. It is delicious. There's nothing in this world that's more important than freedom. And when you lose your freedom, you lose everything. Reporter: He has his freedom, full time job at Stevens' equal justice initiative and has written his own book, "The sun does shine". And his smile. What the criminal justice system took from Anthony ray Hinton, time nor treasures can restore. No one sees when I'm at home by myself the tears. No one sees the scars that is perhaps there forever. Reporter: You still cry? Oh, yes. Reporter: Why? Well, I lived in fear. I fear that any night the police could kick the door down and say I did something. Reporter: Really? Still? Oh, absolutely. If they did it once they could do it again. Reporter: When's the last time you cried? Oh, this morning. I think if people saw what I saw on a regular basis, if they saw children condemned to die in prison, mentally ill people being abused they would want change. But our system is so insulated they don't see it. Reporter: For all the darkness you see you are an optimistic man. I think hopefulness is a requirement to do what I do. But if they take me to that jail tonight I'm going out cause I got my truth back. Reporter: Thanks to Bryan Stevenson, Walter Mcmillen won his freedom in 1993. He died in 2013. For Jordan, one of the film's producers, this was an opportunity to showcase diversity both on and off you push for a collusion rider, which is new. It means that groups are being heavily considered for a major role behind the camera, black and brown communities, minorities. Women, from the lbgtq community. Reporter: What do you want audiences to take from this? I want them to open themselves up. What was great about the movie is it makes them a human story. I want people to be hopeful. I think Bryan Stevenson is the most hopeful, optimistic person there is. I think if we can create a consciousness that bias and bigotry is fundamentally unacceptable in this country, we'll think differently. It won't take six years to get Walter Mcmillen off of death row. Reporter: As Bryan Stevenson knows, justice deferred beats justice denied. But it's a hard-fought hope that assures him, America someday will do better.
This transcript has been automatically generated and may not be 100% accurate.