As Mourning Becomes Electra is consciously based on ancient Greek tragedy, it's not surprising that it contains a number of classical elements. First and foremost, we have a tragic heroine in the shape of Lavinia. As with all tragic heroes, she is a high-born character brought low by a tragic flaw. In her case the flaw happens to be her lustful desires for her father, Ezra.

Due to this flaw, Lavinia engages in unsavory behavior that ultimately leads to catastrophe. When she finds out that her mother Christine killed Ezra with poison, Lavinia convinces her brother Orin to take revenge on Christine. However, far from making things better, Orin's murder of his mother's lover and subsequent driving of his mother to suicide has the exact opposite effect. The incestuous desires between brother and sister are as powerful as those that existed between father and daughter. These desires eventually lead to catastrophe: Orin, in keeping with the traditions of ancient Greek tragedy, kills himself.

In turn, this leads to catastrophe for Lavinia as she experiences the downfall of the tragic hero. Now she is completely alone. Recognizing herself to be the last of the Mannons, she punishes herself by living on her own in the house of the dead, destined to be haunted by the ghosts of the past for the rest of her life.