Depp is best known as the star of "The Pirates of the Caribbean" movie franchise. He also is a frequent collaborator of director Tim Burton.
His next role will be as Bulger in the film adaptation of "Black Mass: The True Story of an Unholy Alliance Between the FBI and the Irish Mob," written by former Boston Globe investigative reporters Dick Lehr and Gerard O'Neill, Deadline.com reported.
Director Barry Levinson is to begin shooting the flick in May.
"[Depp is] certainly one of the best actors of our time and he can certainly fill any role," Lehr told the Globe.
"He's got [the 1970s-set gangster picture] 'Donnie Brasco' under his belt. Now he'll have Whitey Bulger there, too," O'Neill said.
Actor-director Ben Affleck is also working on a bio-picture, with his longtime friend and fellow Boston native Matt Damon set to play Bulger, the Globe noted. That film is being written by "The Sopranos" and "Boardwalk Empire" scribe Terry Winter.
Bulger, 83, is in jail awaiting trial. His lawyers have said he was granted immunity so he would not be prosecuted for any of his crimes, including 19 alleged murders in the 1970s and 1980s, in exchange for acting as an FBI informant. He was arrested June 22, 2011, after 17 years on the run.