The Departed - Characters & Cast

Billy's primary motivation is to prove himself as a legitimate and honorable police officer, to break away from the shadow of his family's criminal past. He is driven by a desire to uphold justice, even at a great personal cost.

Billy begins as a troubled but ambitious police academy cadet who agrees to go undercover to escape his family's criminal reputation. As he descends deeper into Costello's world, the immense psychological strain and moral compromises take a heavy toll, leading to anxiety and a blurring of his own identity. His arc is a tragic one, as his attempts to do the right thing ultimately lead to his demise without his name ever being cleared.

Colin is motivated by a desire for power, status, and the appearance of a perfect, legitimate life. He wants to have it all: the respectability of a high-ranking police officer and the benefits of his criminal connections.

Colin starts as a young boy taken under the wing of mob boss Frank Costello and is groomed to be his mole in the police force. He is ambitious and successful, but his life is built on a foundation of lies. His arc sees him become increasingly paranoid and ruthless as he tries to protect his carefully constructed identity, ultimately leading to his isolation and violent end.

Costello is motivated by a lust for power, control, and the desire to shape his environment to his will. He enjoys the thrill of the criminal life and the manipulation of those around him, particularly the young men he takes under his wing.

Frank Costello is the charismatic and ruthless head of the Irish mob in Boston. He is a powerful and manipulative figure who sees himself as a kingmaker. His arc is one of an aging crime lord who, despite his cunning, becomes increasingly paranoid about a 'rat' in his organization, a paranoia that ultimately contributes to his downfall. It is also revealed that he himself is an FBI informant.

Dignam is motivated by a strong, albeit aggressive, sense of justice and loyalty to his fellow officers, particularly Captain Queenan and Billy Costigan. He has a deep-seated hatred for corruption and those who betray the badge.

Dignam is an abrasive and foul-mouthed but fiercely loyal police sergeant. He is initially one of the few who knows Billy's true identity. After being forced out of the department, he disappears from the narrative, only to return at the very end to deliver his own form of justice, acting as an avenging force outside the corrupted system.