Paul Edgecomb (DABBS GREER) is an old man living in a nursing home whose frequent disappearances and melancholy ways cause his friend, Elaine Connelly (EVE BRENT), to question his behavior. Although initially reluctant, Edgecomb eventually recounts his stint -- some six decades earlier -- as the head guard on Cold Mountain Penitentiary's death row.
Back in 1935 Paul Edgecomb (TOM HANKS) presides over cell block E, also known as the "green mile" for the green linoleum flooring leading from the jail cells to the electric chair where the prisoners will eventually be executed.
They include Arlen Bitterbuck (GRAHAM GREENE), an American Indian and Eduard "Del" Delacroix (MICHAEL JETER), a Cajun man who develops a special friendship with a mouse nicknamed Mr. Jingles. Things change, however, for Edgecomb and his fellow guards, Brutus "Brutal" Howell (DAVID MORSE), Dean Stanton (BARRY PEPPER) and Harry Terwilliger (JEFFREY DeMUNN) upon the arrival of two inmates.
The first, "Wild Bill" Wharton (SAM ROCKWELL), is a persistent troublemaker who agitates the guard team's lone man out, Percy Wetmore (DOUG HUTCHISON), a sadistic brat who gets away with his errant behavior due to his familial ties to the Governor. The other inmate, John Coffey (MICHAEL CLARKE DUNCAN), is a towering specimen of a man whose physically intimidating appearance contradicts his polite and nearly childlike demeanor, including being afraid of the dark.
Despite the rules set forth by Warden Hal Moores (JAMES CROMWELL) -- who's preoccupied with his wife, Melinda (PATRICIA CLARKSON), and her terminal illness -- to carry out every execution, Coffey's behavior causes Edgecomb to question the giant's conviction for apparently killing two girls. It's a later revelation concerning a special gift that Coffey possesses that makes the guard ponder whether he can be responsible for putting the inmate to death.
As the date of Coffey's execution draws near, Edgecomb, with the help of his loving wife, Jan (BONNIE HUNT), must do some deep soul searching while contending with Coffey, Percy and life and death on the Green Mile.