In the spring of 1830 in the Tennessee Valley, Andrew Johnson, a young stranger, falters into the small town of Greenville and thirstily drinks from a water trough in the yard of the village blacksmith, Mordecai Milligan. As Andrew begins to methodically stitch his torn trouser leg, he looks up and sees Mordecai and his companions, Mrs. Fisher and Blackstone McDaniel admiring his mending abilities and staring at the leg iron binding his ankle. When Mordecai tosses him a file, Andrew offers to patch his britches in gratitude and explains that he is a tailor's apprentice who is running away from his servitude. Moved by Andrew's plight, Mordecai uses a hammer and chisel to break the shackles. By enduring the pain of the pounding hammer, Andrew wins the respect of the group, and Mrs. Fisher urges him to stay on as the town tailor. Also witnessing the incident is latecomer Eliza McCardle, Greenville's librarian. Andrew sets up shop, and when Eliza comes one day to pick up a dress she had left along with written instructions. Andrew, an unschooled and inarticulate man, shamefully admits that he cannot read or write and offers to tailor her clothes in exchange for tutoring. Although he proves to be a swift learner, Andrew is embarrassed by his humble beginnings as a non-landowning "mudsill" until he reads the Bill of Rights and is inspired by its precepts that all men are created equal and therefore should have the right to vote. Prodded by Eliza, Andrew enters village politics and finds himself at odds with the property owners represented by Sheriff Cass, who believes that non-land owners should be denied the vote. When Cass comes to ask Eliza, now Andrew's wife, to persuade him to cancel a rally calling for the vote, Andrew, infuriated, pockets his pistol and brusquely proceeds to the meeting. When Cass tries to interfere, a fight ensues and Mordecai is killed in the mêlée. Mrs. Fisher and the others call for retaliation, but Andrew pleads for reason and adherence to the law. With the support of the town, Andrew is elected the new sheriff. With the approach of the Civil War in 1860, Andrew, now the U.S. Senator from Tennessee, opposes succession, arguing that the Union must be preserved at all costs. When succession is declared, Andrew refuses to join his Southern colleagues in their exodus from the Senate chambers and is declared a traitor. As a general in the Union army, Andrew is credited with saving Nashville for the Union. After the war, Abraham Lincoln moves to appoint Andrew his Vice-President over the objections of Thaddeus Stevens, a Pennsylvania congressman who seeks vengeance on the South. Nevertheless, Andrew is appointed as Lincoln's Vice-President, and on inauguration day, Andrew, sick and unused to drinking, imbibes some celebratory brandy, and as a result, is drunk by the time he is sworn in. Andrew believes that he has disgraced his country, but Lincoln, understanding the circumstances surrounding the incident, sends him a letter of forgiveness. When word comes of Lincoln's assassination, Andrew ascends to the presidency, vowing to uphold Lincoln's policy of reconciliation with the South, even though he secretly suffers feelings of self-doubt and inadequacy. Soon after, Andrew is visited by Stevens, Congressman Hargrave and Senator Jim Waters. Stevens, desirous of subjugating the Southerners by confiscating their lands and denying them representation in Congress, offers Andrew a guaranteed second term if he agrees to support his exclusionist policies. When Andrew rejects the offer, Stevens threatens him with impeachment and reminds him that with no Vice President in office, Waters would succeed him. Losing his temper, Andrew denounces Stevens and puts his faith in the people. Upon discovering that one of his Cabinet members has been spying for Stevens, Andrew dismisses the man without consent from the Senate, thus violating the law that prevents a President from dismissing a Cabinet member appointed by a previous President who died in office. Stevens, disabled and suffering from ill health, is invigorated by Andrew's transgression and pulls himself out bed to visit him. Rankled by Stevens' threats, Andrew signs a proclamation pardoning all those who fought in the war between the states. When Stevens offers to halt impeachment proceedings if Andrew rescinds the pardon, Andrew refuses. Contemptuously dubbing Andrew the "tailor," Stevens convenes an impeachment hearing, charging Andrew with being a drunk and violating the Tenure of Office Rule. Following his lawyers' advice, Andrew does not appear at the trial, until one day, Blackstone, now a Senator from Tennessee, informs Andrew that his witnesses will not be allowed to testify. Furious, Andrew bursts in the hearing to defend himself and is greeted by the jeers of the onlookers. Stevens expects Andrew to lose his temper, but instead, he eloquently defends himself by reading Lincoln's letter of forgiveness and accusing Stevens of trying to tear the nation apart, the very antithesis of Lincoln's ideals. As the vote for impeachment is called, Senator Huyler, one of Stevens' minions, faints and is carried out. Aware that he needs Huyler's vote to win, Stevens stalls for time until Huyler can be revived. Disgusted by Stevens' tactics, the Chief Justice ousts him from the hearing. When Huyler, barely conscious, is dragged back into the room, he raises his head and votes not guilty, thus acquitting Andrew. Andrew serves out his presidency, and years later, when he is re-elected to be the senator from Tennessee, he welcomes his colleagues from the South, whose readmittance into the halls of government he helped shepherd.