The cast featured Richard Burton, Maggie McNamara and John Derek, along with Raymond Massey, Charles Bickford, Elizabeth Sellars and Eva Le Gallienne.
Edwin "Ned" Booth (Richard Burton) is the son of the noted thespian Junius Brutus Booth and the older brother of another actor, John Wilkes Booth. Beginning In 1848, as a boy, and into early manhood, he travels with and assists Junius, who is often drunk and seems at times on the brink of madness.
Several years go by. A theater owner, Dave Prescott (Charles Bickford), eagerly anticipates a Junius performance in San Francisco, but the actor is again unable to perform and decides to leave the theatrical run. Junius hands over his crown – a literal theatrical crown worn during his rendition of Richard III, to Ned, who has memorized his father's lines. Ned's first performance is of Richard III during a show at a mining camp, where the miners, disappointed at first, are ultimately pleased by what they see. Prescott, however, breaks the news shortly after that Junius has died.
Ned returns east, where John Wilkes Booth is starring in The Taming of the Shrew to great acclaim at Ford's Theatre in Washington D.C. Billed as the son and successor to Junius Brutus Booth (Raymond Massey), John is planning a tour and asks Ned if he will be his manager along with their younger sister, Asia (Elizabeth Sellars). Somewhat contemptuous of his upstart brother's early success as an actor, Ned declines. He tells his younger brother that he hasn't learned the craft the way he, Ned, has by traveling with, hearing the performances, and looking after their father for many years. Ned begins a theater tour of his own with Dave Prescott. He travels to New Orleans, where he meets, then soon marries, Mary Devlin (Maggie McNamara), a member of a theatrical company who plays Juliet opposite Ned's role as Romeo.
The Civil War breaks out and John is said to be working steadfastly for the Confederacy's cause. He declines an offer from Ned to go to London together for a production of Hamlet, and when a pregnant Mary falls ill, Ned begins drinking heavily and missing performances.
Mary's death turns her husband morose. Then comes the terrible news one night that John Wilkes Booth has assassinated President Abraham Lincoln by gunshot at Ford's theater.
Weeks after the assassination, and his brother's subsequent death on a farm in Virginia, Ned has decided to return to the stage in Hamlet. On opening night the theater is packed by a mob incensed by the murder of the president and blaming not only Booth but all actors and theaters in general. One protestor says the president "died in the very doorway to hell" because he was murdered in a theater.
Backstage, Dave Prescott tells Ned that the show must be canceled. Ned insists that he wants to go on for his profession as well as his family name, remembering that his late wife once said that acting was his gift, his purpose in life and he must "never be derelict" to that purpose.
Ned is seated center stage on the throne as the curtain comes up. The mob hurls insults, vegetables, and other objects at Ned as the other actors rush off the stage. Ned remains seated, immobile, and absorbs the abuse until the crowd's fury exhausts itself. Finally one of the protestors declares "he's got guts", shouts "Booth, you're alright!", and begins clapping.
Gradually more of the mob join him, the other actors return to the stage, and the film ends with Ned hearing his late wife speaking part of Juliet's soliloquy as the crowd's approval continues to rise.