Macheath, also known as Mac the Knife, is a charismatic gangster operating in Victorian-era London. A former soldier, he blends an outward appearance of gentility—often wearing white gloves—with a predatory, violent nature. He leads a local gang of thieves and relies on his charm and corrupt connections to evade the law.

Jonathan Jeremiah Peachum is the cynical owner of "The Beggar's Friend Ltd." He maintains a strict monopoly over begging in London, requiring destitute individuals to pay him a fee for the right to beg. He treats his business and his family with cold calculation, viewing everything through a lens of profit and exploitation.

Polly is the supposedly innocent daughter of the Peachums who defies her parents to marry Macheath. Though initially presenting a romanticized view of love, she quickly demonstrates an ambitious edge. She struggles to reconcile her middle-class upbringing with the dangerous reality of her new husband's criminal enterprise.

Celia Peachum is Jonathan's pragmatic wife who assists in managing the begging ring. She shares her husband's prioritization of financial gain over familial affection. When she discovers her daughter's romantic involvement with a notorious criminal, she quickly joins forces with her husband to protect their business operations.

Tiger Brown is the high sheriff of London and an old army friend of Macheath. He maintains an illegal alliance with the gangster, actively erasing criminal records in exchange for loyalty and mutual benefit. His character represents the hypocrisy of institutional power, as he attempts to balance his public duties with his private friendships.

Lucy is Sheriff Tiger Brown's daughter. She shares a romantic history with Macheath, putting her in direct competition with Polly Peachum. Despite her father's position in law enforcement, Lucy is deeply entangled in the criminal underworld and proves adept at outmaneuvering her rivals.

Low-Dive Jenny is a sex worker operating in London and a former lover of Macheath. Her relationship with the gangster features both lingering nostalgia and deep bitterness over past mistreatment. She survives in a brutal patriarchal society by making self-interested choices to ensure her own financial security.

Reverent Kimball is a local parson who officiates the marriage between Polly and Macheath. He conducts a sacred ceremony in a stable filled with stolen goods, exposing the moral ambivalence of the society.

Charles Filch is a desperate young man seeking to earn a living on the streets of London. After facing violence for begging without permission, he reluctantly pays a fee to join Peachum's organized ring. He gives up his earnings and dignity in exchange for a licensed beggar's costume.

Smith is a constable in the London police force. He operates within a completely corrupt law enforcement system, treating justice as a commodity. He willingly accepts bribes and carries out the orders of whoever holds the most leverage.

Composed of thieves like Matthew, Crook-fingered Jake, and Dreary Walter, this collective serves as Macheath's muscle. They operate under a strict hierarchy and admire Macheath's professionalism, though their loyalty depends entirely upon their own self-preservation and financial success.