Abandoned by his father, Jack suffers from the lack of a father figure. As Jack grows up he never deals with his father's abandonment and also avoids dealing with the pain he causes others. Jack stops writing a college paper about his great-uncle, Cass Mastern, when he learns about Cass's dilemma about the suffering he caused. Jack often copes with his problems by immersing himself in a depressed state called the Great Sleep. Jack falls in love with Anne Stanton and asks her to marry him. Even though she loves him, she rejects the offer because of Jack's aimless life. He finds purpose working for Willie, the governor of the state, finding scandals about Willie's enemies. To avoid taking responsibility for his actions, Jack has adopted the Great Twitch theory, which claims that people just respond to impulses. However, after the man he learns was his real father commits suicide and Willie is assassinated, Jack decides to take responsibility for his life. He is also able to fully accept his past.
Willie Stark is born and raised in a small town in a southern state. Full of energy and ambitious to do good in the world, Willie educates himself enough to pass the bar examination. His first run for election shows him that politics are tainted and an honest approach does not win. His ambition and pride are awakened, and in the next election for governor his fervent speeches—and corrupt practices—get him elected. As governor Willie uses bribery and blackmail to get what he wants. Also inspired by an adoring constituency, Willie comes to view himself as above the law. He has many affairs with women, including Anne Stanton. Despite his corruption, Willie clings to the ideal of building a great hospital, but he uses coercion to get Anne's brother, Dr. Adam Stanton, to run the institution. When Willie's son becomes paralyzed from a football injury, Willie comes to see his limitations and starts to reform his ways. However, his good intentions are cut short when Adam, enraged about his sister's affair with Willie, assassinates him.
Anne Stanton comes from an elite family in a southern state where her father served as governor. She has an older, idealistic brother, Adam, who becomes a renowned surgeon. Anne has a pureness about her. She sees herself and her family as people who are honest and above corruption. Anne falls in love with Jack Burden, who loves her but leads an aimless life. Anne, though, believes in engaging fully in life and, as a result, Jack's passive attitude and lack of any future plans bothers her. Because of this Anne turns down Jack's offer to marry her. Anne's world changes when Jack tells her that her deceased father was involved in a scandal as governor. Her idealistic view of her family and of her father as paragons of virtue comes crashing down. Disillusioned, she has an affair with Willie. Jack is devastated by the affair, but Adam is outraged. He assassinates Willie and is killed himself. Over time Anne gradually recovers and renews her friendship with Jack, who has adopted more of a responsible approach to life. When Jack again asks her to marry him, this time she accepts.
Adam Stanton is an idealistic man who tends to see the world in black and white. Like his sister, Anne, Adam sees his father, a former governor of the state, and his family as paragons of virtue. He wants to do good in the world and becomes a renowned surgeon. However, he is so fanatical about helping others that he lives below his means in a small, dingy apartment. Adam is still close to his childhood friend Jack Burden. Although Jack works for Willie, the corrupt governor, Adam does not condemn him but wants nothing to do with Willie himself. As a result, when Jack asks him to run Willie's hospital Adam refuses. But when he learns about his father's scandal during his term as governor, Adam's view of the world changes. He accepts the hospital position but still resents working for Willie. When Adam is told that he got the job because his sister agreed to sleep with Willie, the insult is more than Adam can tolerate. He assassinates Willie and is then himself shot to death.
As a member of an elite family, the judge strongly influences the politics in his state. He appears to be a noble person who served honorably as a lawyer and a judge. He is a friend of Jack Burden's family and treats Jack with affection, like a surrogate father. However, the judge has another side, which Jack discovers when Willie tells him to find a scandal about the judge. At one time the judge had financial problems and accepted a bribe not to prosecute a case. Also he accepted a plum job, which resulted in an honest worker getting fired and committing suicide. Jack finds documents that prove the scandal and tries to blackmail the judge into supporting Willie. Instead, however, the judge commits suicide. Only afterward does Jack learn the judge was his real father, whom Jack's mother loved. His history and his suicide reveal him to be someone who valued keeping up a noble appearance more than anything.
Sadie Burke comes from a poor, rural family whose face still bears pockmarks from a childhood case of smallpox. She is an intelligent, dynamic woman who claws her way into a prominent position in politics. Along the way Sadie becomes cynical about politics but enamored with political power, especially as personified by Willie. She also has become embittered by the treatment she has experienced for being a woman in politics, coming from a poor background, and being scarred by smallpox. Willie's mistress, Sadie is jealous of her lover's other affairs—jealous enough to start the chain of events that lead to Willie's assassination.
Jack's mother, who remains unnamed in the novel, comes from a poor Arkansas family. She loves Judge Irwin and bears his son, Jack. However, the judge refuses to marry her and divorce his wife. As a result she marries Ellis Burden to save face and pretends that he is Jack's real father. Eventually, she divorces Ellis and has affairs with other men. Jack's mother relies on her beauty to find love. She easily attracts men, partly because of her looks and partly because of the money left to her by Ellis. She even uses her physical allure to influence Jack. However, she fails to admit her true feelings, and she is the reason Jack has no father figure. Only after the judge's suicide does Jack's mother admit to her son that she loved the judge, who is his father. She also admits the mess she has made of her life, helping Jack to find the peace he needs.