Content warning: This section of the guide discusses gender discrimination, sexual content, death, and violence. 

Macheath is the play’s main character. He is a charismatic and ruthless criminal who blends charm and brutality. As a protagonist with strong antiheroic qualities, he embodies the contradictions of a corrupt society due to being both a predator and the victim of a system built on exploitation: In his apparent urbanity, he is a stand-in for the corrupt upper classes, yet at the same time, the play highlights the fact that a small-time criminal like Macheath is vulnerable in ways that the societally sanctioned criminals in business and politics are not. 

This is not to say Macheath entirely lacks institutional power. Macheath served in the army, where he met Sheriff Tiger Brown, who (despite nominally being on the side of the law) continues to be his friend and business partner until he is forced to turn Macheath in due to being threatened by another local gangster—Peachum. Both in his relationships to other characters and his own narrative arc, Macheath is thus central to the play’s exploration of Corruption as a Universal Constant. 

Mac the Knife marries Polly but maintains relationships with multiple women, which illustrates his manipulation and self-interest.