Michael Clarke Duncan, who rose from working as a ditch digger to employ his booming bass voice and immense physical presence in many movie roles, most notably a tragic prisoner with a healing touch in the 1999 film “The Green Mile,” died on Monday in Los Angeles. He was 54.


His fiancée, the Rev. Omarosa Manigault, said the cause was complications of a heart attack he had on July 13, his publicist, Joy Fehily, said.


Mr. Duncan was nominated for both an Academy Award and a Golden Globe for his supporting role in “The Green Mile,” in which he played John Coffey, a mysterious stranger convicted of the rape and murder of two little girls in Louisiana in 1935. Janet Maslin, writing in The New York Times, referred to the “peculiar innocence” with which Mr. Duncan, who was 6-foot-5, imbued the character.


Mr. Duncan’s other movie parts included Bear, one of the deep-sea oil drillers who volunteer to save Earth by blowing up an asteroid, in the 1998 blockbuster “Armageddon.” He played small parts in many other movies, including “Planet of the Apes” (2001), “Daredevil” (2003), “Sin City” (2005), “The Whole Nine Yards” (2000) and “The Scorpion King” (2002).


He also lent his voice to animated movies like “Cats and Dogs” (2001); “Brother Bear (2003) and “Kung Fu Panda” (2008), as well as episodes of the television cartoon series “Family Guy.” The television shows on which he appeared included “Two and a Half Men” and “George Lopez.”


Mr. Duncan was born poor on the South Side of Chicago on Dec. 10, 1957. His father left when he was 5, and his mother and older sister raised him. He attended Kankakee Community College in Illinois and Alcorn State University in Mississippi, where he played football and basketball. He majored in communications, but returned to Chicago before receiving his diploma to help support his family.


Mr. Duncan worked as a ditch digger for the Peoples Gas Company, as a nightclub bouncer and even as a stripper, under the name Black Caesar. His mother, who had dreamed of becoming an actress, urged him to try acting, and he moved to Los Angeles, where he worked as a bodyguard for stars like Will Smith, Martin Lawrence and Jamie Foxx. That led to a succession of minor roles, many as a bouncer.


While filming “Armageddon,” Mr. Duncan struck up a friendship with his fellow cast member Bruce Willis, who called the director and screenwriter Frank Darabont, who was casting “The Green Mile,” based on a book by Stephen King, and recommended him for the part of Coffey. He got the part, and he then rose to what he characterized as a major challenge.


“I think the toughest scene for me to film was the two dead girls, simply because I had a lot of crying to do, a lot of howling to do, and it took a long time to do it and it really drained me,” he said in an interview with The Akron Beacon Journal in 1999.


“I’ll remember that day more so than anything else because as we were filming that, everybody was rushing toward me,” he continued. He said the scene seemed so real that he felt scared every time Mr. Darabont said, “Roll.”


Mr. Duncan narrated the Major League Baseball film on the 2005 World Series, which the Chicago White Sox won. He also appeared in a public service announcement about the importance of recognizing the early symptoms of strokes, and in a video for PETA, the animal rights organization, in which he spoke effusively about the positive change he experienced when he became a vegetarian.


In addition to his fiancée, who is best known for her appearances on Donald Trump’s reality show, “The Apprentice,” he is survived by his mother, Jean Duncan, and his sister, Judy Duncan.


Mr. Duncan enjoyed the fame that came with his many movie roles and his distinctive physical appearance. He was known to offer $5 to strangers on the street who could tell him what his full name was.


He told The Commercial Appeal in Memphis that when he learned of his Oscar nomination, he was so excited that he “could have taken on Mike Tyson and Evander Holyfield and the Rock.” The newspaper’s reporter suggested that he probably could have done that regardless of the Oscar.


“Not all at the same time, man,” he said.