Duncan had a handful of minor roles before "The Green Mile" brought him an Academy Award nomination for best supporting actor. The 1999 film, based on the Stephen King novel of the same name, starred Tom Hanks as a corrections officer at a penitentiary in the 1930s. Duncan played John Coffey, a convicted murderer with a surprisingly gentle demeanor and extraordinary healing powers.
Duncan's performance caught on with critics and moviegoers and he quickly became a favorite in Hollywood, appearing in several films a year. He owed some of his good fortune to Bruce Willis, who recommended Duncan for "The Green Mile" after the two appeared together in "Armageddon." Clarke would work with Willis again in "Breakfast of Champions," ''The Whole Nine Yards" and "Sin City."
His industrial-sized build was suited for everything from superhero films ("Daredevil") to comedy ("Talledega Nights," ''School for Scoundrels"). His gravelly baritone alone was good enough for several animated movies, including, "Kung Fu Panda," ''Delgo" and "Brother Bear." Among Clarke's television credits: "The Apprentice," ''The Finder," ''Two and a Half Men" and "The Suite Life of Zack and Cody."
Born in Chicago in 1957, Duncan was raised by a single mother whose resistance to his playing football led to his deciding he wanted to become an actor. But when his mother became ill, he dropped out of college, Alcorn State University, and worked as a ditch digger and bouncer to support her. By his mid-20s, he was in Los Angeles, where he looked for acting parts and became a bodyguard for Will Smith, Jamie Foxx and other stars. The murder of rapper Notorious B.I.G., for whom Duncan had been hired to protect before switching assignments, led him to quit his job and pursue acting full-time.
Early film and television credits, when he was usually cast as a bodyguard or bouncer, included "Bulworth," ''A Night at the Roxbury" and "The Players Club."