His publicist released a statement from his fiancee Omarosa Manigault-Stallworth, saying the actor died Monday morning at Cedars-Sinai Medical Center in Los Angeles after nearly two months of treatment in response to a heart attack July 13.
Duncan is best known for his performance in the 1999 prison drama "The Green Mile," starring Tom Hanks. The actor has also appeared in "Armageddon," "The Scorpion King," and "Sin City." The muscular, 6-foot-4 Duncan worked as a bodyguard before turning to acting in his 30s.
Hanks released the following statement Monday afternoon:
"I am terribly saddened at the loss of Big Mike. He was the treasure we all discovered on the set of 'The Green Mile.' He was magic. He was a big love of man and his passing leaves us stunned."
According to Duncan's publicist, both private and public memorial services will be announced at a later date.
The Associated Press contributed to this report.