The movie opens with a group of people running through a field of wheat, frantically searching for something or someone. We then hear an unfriendly voice saying "You love your sister? You make any noise, know what happens?"The movie then proceeds with an old man in a retirement center named Paul Edgecomb (Dabbs Greer), waking up from an unpleasant dream. He takes two pieces of dry toast from an orderly, who mentions Paul's habit of taking long walks outside the ground. The orderly is worried about Paul, but allows him to continue with his daily routine.Paul and several other residents are watching TV when an old movie with Fred Astaire dancing to the song "Heaven" is on. Paul sees it and is suddenly overcome by emotion, so he walks away, followed by his friend Elaine (Eve Brent). Elaine realizes that the movie has awakened some powerful memories in Paul, and asks about it. Paul tells Elaine his story: he was a prison guard during the Depression, in charge of Death Row, informally called "The Green Mile," because of its green tile floor. Paul's most powerful memory of this time took place in 1935....The story then flashes back to the 1930's at the Louisiana State Prison, where a young Paul Edgecomb (now played by Tom Hanks) suffers from a urinary infection. Some of the other guards- Brutus "Brutal" Howell (David Morse), Dean Stanton (Barry Pepper), Harry Terwilliger (Jeffrey DeMunn) and Percy Wetmore (Doug Hutchison) - bring in a new inmate. Percy makes quite a spectacle out of the arrival, repeatedly yelling "Dead man walking!" through the complex, to the annoyance of the other guards. The convict's name is John Coffey (Michael Clarke Duncan) "like the drink, only not spelled the same." He is a gigantic muscular black man, but when Paul talks to John, they find that he has the mindset of a small child- very meek and apparently scared of the dark. After John has been placed inside his cell, he mysteriously states that he "tried to take it back, but it was too late."Paul confronts Percy with his constantly rousing behavior, but when Percy shows nothing but disrespect for authority, Paul sends him off the Mile to attend work elsewhere. Percy is not happy about this, and in frustration, he lashes out at another inmate named Eduard 'Del' Delacroix (Michael Jeter), breaking Del's fingers. Paul is given a copy of John Coffey's records, and finds that he was sent to Death Row after being convicted for the murder (and implied rape) of two small girls. After the two girls went missing, a posse went looking for them, finding John sitting in an open field, crying uncontrollably while holding the dead girls in his arms. As he was arrested, John stated that he "tried to take it back, but it was too late."Later on, Paul is outside when he is met by warden Hal Moores (James Cromwell). Hal gives Paul the execution papers for an inmate named Arlen Bitterbuck (Graham Greene), and has a conversation with him about Percy. It's revealed that Percy is the nephew of the governor's wife, and his powerful political connections are what got him hired- and keep him in the job, because Percy is apparently "stupid and mean" according to the other guards. Paul finds out that they have already received a complaint about Percy being removed from the Green Mile, even though he broke an inmate's fingers. However, Hal has also learned that Percy has applied for an administrator job at a mental hospital, which would mean better pay and better hours, and with a little luck, no more Percy on the Mile. Paul theorizes that Percy wants to witness an execution up close before moving on to a new job. Warden Moores also mentions that his wife, Melinda, is not well. She suffers from bad headaches and is scheduled for an X-ray in order to find the source of the problem. That night, Paul talks about John Coffey and his concerns for Melinda with his wife Jan (Bonnie Hunt). He also regrets that they cannot make love as long as he has his infection, but waves away her advice to see a doctor for it.Next day, Brutus spots a mouse in the cell block. They watch it run into a small room in the corner, which turns out to be a padded room for dangerous inmates but is currently used for storage. The guards check everything in the room but do not find the mouse. A few hours later, Percy arrives, spots the mouse and goes into a fury trying to kill it. The mouse goes back into the padded room, and Percy intends to go in. The other guards purposely don't tell him that they already tried that, and watch in amusement as Percy unpacks the entire room again, to no avail. Afterwards, Paul berates Percy for scaring the inmates in his pursuit of the mouse. Percy doesn't care, thinking the inmates are contemptible. Paul feels differently, believing that the inmates are under enough stress since they are waiting to die; if put under more strain, they could "snap" and cause serious problems. After more of Percy's insolence, Brutus grabs him, but Percy threatens to use his connections as nephew to the governor's wife to get the others fired if they hurt him. Paul retorts that if he ever makes such a threat again, they will "have a go" at him, even at the cost of their jobs.While Bitterbuck is granted one final meeting with his family, Paul and the others prepare the auditorium with the electric chair for his upcoming execution. They do a rehearsal with the prison's elderly janitor, Toot-Toot (Harry Dean Stanton) helping them. Paul instructs Percy to watch and learn while the others prep the electric chair. One of the guards explains to Percy the necessity of putting a wet sponge on the convict's head before the cap with the electrodes is attached; this will cause the electric current to go straight through the head, and allow the execution to go more smoothly. That night, Bitterbuck is prepared for the execution. In his final talk with Paul, he recalls his most pleasant memory, and asks Paul if he believes that if a man repents for his crimes, that he will go back to the time that he was most happy. Paul says he believes that exact thing. Brutus leads Bitterbuck's execution, which is carried out with little problems (although Bitterbuck needs two jolts of electricity before his heart stops). Afterward, Paul confronts Percy with his new job opportunity, stimulating him to take it now that he has witnessed an execution. However, Percy reveals that he wants to be "out front" (placed in charge of an inmate's execution) before he leaves.Next day, the inmate named Del has found the mouse again, named it "Mr. Jingles" and is trying to tame it. The mouse is able to fetch a spool of thread as a trick. The other guards allow Del to keep Mr. Jingles as a pet. Even Percy is uncharacteristically supportive of this, suggesting they get the mouse a cigar box to sleep in.Paul meets with Warden Hal again, getting word of a new inmate coming in, a man named William 'Wild Bill' Wharton, who killed three people in a holdup. Hal is almost in tears; the doctors have told him that his wife Melinda has a tumor the size of a lemon in her brain, virtually inoperable and eventually fatal.That night, Paul suffers from his urinary infection even more; he is almost in constant pain. He intends to see the doctor the next day after the new inmate has been brought in. Percy and Harry go to retrieve Wharton from the mental hospital, where he is in an apparent trance, presumably from medication. As soon as Wharton enters the Mile, he springs to life, clearly having faked his drug-induced stupor. He surprise-attacks the guards and incapacitates Paul by kneeing him in the groin. Dean is nearly strangled, and Percy is nailed to the floor in shock, unable to intervene despite Paul's cries for help. Finally, Brutus comes in and takes Wharton out. Paul urges the others to go and report what has happened, and stop by the medical facility, while he will hold the Mile. As soon as the others have left, he collapses in pain. John Coffey then asks to speak with Paul. With great effort, Paul approaches John's cell, but John grabs Paul and puts his hand over Paul's groin. John holds on for several seconds, until the lights flare brightly. John then lets go, coughing and gasping until he releases a cloud of gnat-like spores from his mouth that disappear in the air. Paul asks what happened, but John can only say "I helped". He becomes tired and goes to sleep. Later, when Paul visits the washroom, he feels no pain at all: John Coffey's act has healed his infection. Paul comes home and feels completely reborn, making love to his wife almost all night.The next morning, Paul calls in sick for work, but goes into town to see John Coffey's public defender, Burt Hammersmith (Gary Sinise) who preceded over John's trial. Paul voices his doubt about Coffey, no longer believing that such a kind and gentle man could be responsible for such a horrible crime. Hammersmith, however, is absolutely convinced of Coffey's guilt, and compares John to the dog that attacked his own son one day for no reason.The next day, Paul presents John with a loaf of cornbread baked by his wife, as a thanks for Coffey's "help". Coffey shares the cornbread with Del and Mr. Jingles, but does not give any to Wharton, who is blatantly racist. This enrages Wharton, who takes his fury out on the guards over the next few days. He urinates on Harry's shoes and spits the chocolate filling from a Moon Pie all over Brutus, so the guards use a fire hose to catch Wharton off guard, then wrap him up in a straitjacket and send him to the padded room. Despite Wharton's promise to behave every time he gets out, the padded room becomes his frequent residence for a while.Del's execution is coming nearer, and the guards are having a talk with him about it. Del's main concern is what will happen to Mr. Jingles. Brutus suggest sending him off to a magical place called 'Mouseville' in Florida, but first, they feel that Del should do a show with Mr. Jingles for the prison staff.The rehearsal for Eduard Delecroix's execution takes place the next day, as Del performs his show with Mr. Jingles. Paul has decided to put Percy in charge, in the hope that he will finally leave the prison immediately afterward. Del's show is a big success and Percy's rehearsal went well too, so both men seem to be on good terms for a change. However, in a momentary lapse of concentration, Percy walks too close to the cells and is grabbed through the bars by Wharton. Wharton menaces Percy for a while before letting him go, and Percy wets himself in terror. Ashamed, he threatens the guards to never mention this to anyone. Paul states that "what happens on the Mile, stays on the Mile." They will not say anything about what happened. Del, however, delights in Percy being humiliated, much to Percy's anger.Later on, Mr. Jingles runs across the room between cells. Percy walks up and stomps on the mouse, coldly uncaring about what he has done, leaving Del screaming in agony. John Coffey asks for the mouse, so Paul picks it up and hands it to John. The other guards watch in shock, awe, and possibly horror as light shines from John's hands. John coughs, releases another cloud of spores, and Mr. Jingles runs across the room -- as good as new. Percy, seeing that the mouse is uninjured, is furious - thinking the guards have set out to make a fool out of him. Paul confronts Percy and gives him an ultimatum- Percy will transfer out immediately after Delacroix's execution, or the others will go public about Percy's record of mistreatment of the prisoners and his inadequate behavior on the Mile. Percy agrees.The night of Del's execution has arrived. Just before he "walks the Mile" to the electric chair, Del gives Mr. Jingles to Paul, knowing that he will be taken care of. When Paul points out that he cannot have a mouse sitting on his shoulder during an execution, John Coffey volunteers to take care of Mr. Jingles.Del is placed on the chair in front of the audience as Percy starts the ceremony. As his last lines, an emotional Del asks for forgiveness for his crimes, and asks Paul not to forget about Mouseville. Percy deviously responds by saying that Mouseville isn't real; the men only mentioned it to keep him quiet, which upsets both Del and the guards. Percy proceeds by hooking Del up to the electrodes, with one small exception- he purposely does not soak the sponge he places on Del's head, wanting to punish Del one more time. Paul notices that the sponge is dry, but just too late: the electricity has already been activated. As a result, the execution is excruciating for Del: he convulses and screams in pain, much to the increasing horror of the audience. At the same time, John Coffey is hysterically crying as he seems to telepathically feel Del's struggle. Wild Bill, however, is ecstatically jeering and shouting in joy over Del's ordeal. Paul and the other guards watch apprehensively, but don't dare turn off the electricity, thinking that it will not take much longer. However, they are sadly mistaken - Del's agony is prolonged to the point where he even catches fire. The horrified audience starts to panic and flees the scene, despite Hal Moore's assurance that everything is okay. Paul notices that Percy is averting his eyes, but forces him to watch until Del finally dies. Brutus orders him to put out the fire with an extinguisher.Afterwards, Percy claims he didn't know that the sponge needed to be wet, upon which Brutus violently punches him. Paul restrains Brutus, saying what's done is done, and Percy isn't worth fighting over. Hal comes in and angrily demands to know what went wrong. Paul blames Percy's inexperience for the disastrous execution, but adds that Percy was about to accept his new job at the mental institution anyway, cleverly forcing him to honor their agreement. Upon returning to the Mile, Paul finds that Wharton has ripped up his mattress and is cheerfully singing in celebration, but stops when he is threatened with solitary confinement for the rest of his time. Paul talks to a grief-stricken John. Mr. Jingles, who was in John's hands when it happened, must also have felt Del's pain, and has fled; John does not expect him to return.Paul and his wife go to visit Hal and Melinda the next day. Melinda seems pretty well, but Hal reveals that she is rapidly falling apart. She is losing her memory and experiencing severe behavioral changes, including uncontrollable cursing. Paul decides to invite the other guards (minus Percy) to dinner later and discusses John Coffey's acts of healing both him and Mr. Jingles. Paul states that he can no longer watch what is happening to Melinda, so he wants to sneak John Coffey out to try and heal her. The others are very skeptical, pointing out that Coffey is a convicted murderer, and it would be disastrous if they would be discovered, or if he escapes. Paul puts forth his belief that Coffey is innocent; he "does not see God putting a gift like that in the hands of a man who would kill a child." The other guards agree to help, thinking it is worth the risk. Most of the men have grown-up children, but since Dean's children are still young, he will stay behind on the Mile so that he has plausible deniability in case something goes wrong.The next day, they carry out the plan. Paul brings some drinks, and offers one that is drugged to Wharton , which puts him to sleep. The others then gag Percy, put him in the straitjacket and place him in the padded room for a few hours, supposedly as "retribution" for what he did to Eduard Delacroix, but in reality so that he will not see them leaving. Dean has memorized a cover story in case that someone comes over: John Coffey went crazy and attacked the guards, so they put him in the padded room (which would explain any sounds coming from it) while the rest is at the medical facility. They open up John Coffey's cell, and he is excited at the prospect of going for a ride outside and help Melinda. However, on their way out, Wharton, not entirely out cold yet, grabs Coffey's arm. John is apparently horrified by what he sees when touching Wharton, who finally falls asleep.They arrive at Hal's home, and Hal threatens them with a shotgun, thinking there is a prison riot or escape attempt going on. Paul carefully talks him down, while Coffey goes upstairs to meet Melinda. John gets very close to Melinda's face, and something comes out of her mouth and into his, making the light in the room shine intensely, even causing a small earthquake. John breaks the connection with her, falling down coughing. Melinda sits up, looking much healthier and having no memory of anything that happened before her X-ray. Hal collapses, weeping at his wife's restoration. John continues to cough, unable to release the "spores" like before. Melinda gives Coffey a pendant with the mark of St. Christopher the healer as a present.The men return to the prison, and John is still very ill from the encounter. Dean mentions that Wharton has almost regained consciousness, so they quickly put John back in his cell. Percy is released from solitary, looking aggravated. Paul tells him to take it like a man, and Percy responds that he is going to give it some serious thought. The others fear that he will talk about this one day, but that is a worry for another time. As Percy leaves, John grabs him through the bars, holds his face close to his, releases the spores directly into Percy's mouth, and lets go of him. Percy, in a daze, walks over to Wharton's cell. Wharton, just coming to, taunts him some more. Percy, a tear running across his face, empties his revolver into Wharton's chest. The others seize Percy, who leans back and coughs up the remaining black spores.Paul asks John why he did this. John states that Wharton and Percy were "bad men", and he punished them for it. He tells Paul that he needs to see for himself, and sticks out his hand. Over the protests of the other guards, Paul takes John's hand, and immediately starts seeing the memories of Wharton that John is carrying. Wharton was a worker on the farm where the two little girls lived. One night, he snuck into their room and abducted them. He threatened them that if one would scream, he would kill the other. While the electricity around them goes haywire again, Paul sees that Wharton was responsible for the double murder that John Coffey was convicted for. After finally letting go, John tells a devastated Paul that Wharton killed the girls with their love for each other. He is constantly plagued by horrible images like this, and the whole ordeal has exhausted him now.Hal and the police arrive at the Mile, where Percy, upon examination, appears to be catatonic. Hal tells Paul that he will cover for him and his men as much as he can, even at the cost of his job, but he needs to know if any of this is connected to what happened at his house. Paul thinks for a while, but denies it. Percy is taken away and sent to a mental hospital, ironically the same place where he was supposed to be an administrator. He is put in the same room where he once picked up Wharton, presumably to stay there for the rest of his life.Now that he knows Coffey is innocent, Paul is unsure how to proceed. He talks to his wife that night and she suggests talking to John to see what he wants. The next day, Paul and the others have a talk with Coffey, even asking him if they should just "let him go." Coffey does not want to escape, as he doesn't want to get them in trouble. With regards to the upcoming execution, Paul asks John how he could ever justify killing an innocent man before God. John tells him not to worry; he reveals that in addition to healing, he can also feel the pain of all others around him. He does not wish to continue with such pain and darkness in the world, so the execution would be an act of kindness, even for a crime he did not commit. Paul offers John a last request; Coffey states that he has always wanted to see a "flicker show" (a motion picture). They bring in a movie projector with the film "Top Hat," the same movie that the elderly Paul was watching at the beginning of the movie, which is what triggered Paul's memories, particularly when Fred Astaire is dancing to "Heaven". John watches in awe, saying "they like angels!"The day of John's execution finally arrives. Paul has to take John's pendant, but promises to return it to him after his death. The guards take John to the auditorium, where John senses immense hostility from the audience, which prominently features the dead girls' parents who loudly jeer at him. Brutus tells John to focus on the feelings of the guards, who have nothing but sympathy for him. John is strapped to the chair as the guards watch on in tears. As per John's tearful request, Paul does not put a hood over his face, as he is still scared in the dark. Paul makes extra sure that the sponge is wet before placing the cap. Before giving the order to activate the electricity, Paul steps up and shakes John's hand. Again, he hears John's voice saying "he killed them with their love". As the chair is activated, the execution goes smoothly, and John dies. Afterwards, Paul puts the pendant back on his neck. The elderly Paul's voice cuts in and states that he and Brutus left The Green Mile soon after, unable to carry on after seeing John Coffey die. They transferred to a youth corrections' facility.Elaine admits that Paul's tale is "quite a story," but she does not completely believe it. She points out that something does not add up: Paul mentioned his son being grown up in 1935, which means he should be much older than he appears.Paul takes Elaine on a walk, and they come to a cabin in the woods. There is a mouse sleeping in a small box; Elaine is shocked to meet Mr. Jingles. We see a flashback to Paul returning to the Mile shortly after John Coffey's execution: he finds the mouse again, and has kept him ever since. The cabin is not exactly Mouseville, but it is a good place for him. Old Paul states that he is now 108 years old, and that he believes John Coffey "infected him (and Mr. Jingles) with life." He thinks that Mr. Jingles was probably an accident: when John held him during Del's execution, he inadvertently gave the mouse the gift of longevity; Paul received it when he took John's hand after Wharton's death. Paul feels that this is his punishment for killing a genuine miracle of God - he must stay alive and watch everyone he cares about, including friends like Elaine, grow old and die before his own death. He has already survived his friends from the Mile, Hal and Melinda, his wife Jan, and even his son.Later, Paul is seen at Elaine's funeral, quietly wondering just how much longer he has to go on. He has no doubt in his mind that he will die one day, but if God can extend the life of a mouse for so many years, how long does he need to go one living? "We each owe a death," he states, "There are no exceptions. But oh God, sometimes The Green Mile seems so long." The film ends with close-up of Mr. Jingles sleeping.