Mark Antony: Mark Antony is Julius Caesar's right-hand man and personal friend. He is known as a man who likes to spend the nights in feasting and revelry. He enjoys sports and theater. It is Antony's cunning speech to the masses after Caesar's death that turns public opinion against the assassins, who gravely underestimated and misread him. He shows magnanimity in victory.   

Artemidorus of Cnidos: Artemidorus of Cnidos is a teacher of rhetoric who tries but fails to warn Caesar of the plot against him.

Decius Brutus: Decius Brutus is one of the conspirators against Caesar.

Marcus Brutus: Marcus Brutus is recruited for the assassination by Cassius. He becomes part of the plot because he is concerned about the welfare of Rome. He does not covet power for its own sake, and nor does he have any personal complaint about Caesar.  He is presented throughout as a man of courtesy and honor, although perhaps also as a man who is unsuited to wield political power. After he is dead, Antony salutes him as "the noblest Roman of them all."

Julius Caesar: Julius Caesar is the ruler of the Roman Empire. He is presented as a man of strong will and self-belief. He is used to issuing commands and being obeyed. He is stubborn and will not listen to pleas for mercy if he thinks he is in the right. He considers himself to be resolute and unwavering, and he is also perceptive, realizing that Cassius is a dangerous man. But he denies he is afraid of Cassius and claims not to fear anyone or anything. The conspirators believe Caesar is too ambitious and will soon acquire such power that Rome will be enslaved to one man. Although Caesar is a commanding figure, he is physically weak, suffering from epilepsy as well as deafness in one ear.

Octavius Caesar: Octavius Caesar becomes one of the three rulers of the Roman Empire after Caesar's assassination. He is young, and Cassius contemptuously refers to him as a schoolboy.  

Calphurnia: Calphurnia is the wife of Julius Caesar. She has a nightmare in which she sees Caesar's statue running blood, and she begs Caesar not to go to the Senate that day.

Casca: Casca is one of the conspirators, and it is he who stabs Caesar first. Casca is known for his wit and liveliness. He is a man of action who can get things done.

Cassius: Cassius is the chief conspirator against Caesar. It is he who recruits Brutus and the others. Cassius is consumed with envy of Caesar, and sees no reason why Caesar should hold power over him. Cassius is a good observer of men and he has uncommon insight into people's motivations. He is a serious man who reads a lot and does not smile much. Caesar observes that Cassius has a "lean and hungry look." Unlike Antony, he does not like music, and is in every way a contrast to the more sociable Antony.

Young Cato: Young Cato is a friend of Cassius and Brutus. He dies a courageous death on the battlefield.

Cicero: Cicero is an old Roman senator with a reputation for wisdom. The conspirators debate whether to include him in their plot, but decide against it.

Metellus Cimber: Metellus Cimber is one of the conspirators against Caesar. Moments before the assassination, he pleads with Caesar to rescind the banishment of his brother.

Cinna: Cinna is a Roman senator who is one of the conspirators against Caesar.

Cinna the poet: Cinna is dragged off by the mob after the assassination of Caesar, even though he is not the same person as Cinna  the conspirator.

Clitus: Clitus is a servant of Brutus who refuses to kill his master when Brutus asks him to.  

Dardanius: Dardanius is a servant of Brutus who refuses to kill his master when Brutus asks him to.  

Flavius: Flavius is a tribune who is executed for removing crowns placed on Caesar's statues in Rome.  

Caius Legarius: Caius Legarius is one of the conspirators against Caesar. He is eager to join the conspiracy in spite of the fact that he is sick.

Lepidus: Lepidus is one of the three men who rule the Roman Empire after Caesar's assassination. However, Antony holds a very low opinion of him.

Lucilius: Lucilius is a friend of Brutus and Cassius who impersonates Brutus on the battlefield. When Lucilius is captured, Antony prizes him highly and treats him well.

Lucius: Lucius is a servant of Brutus.

Messala: Messala is a devoted friend of Cassius who participates in the battle at Philippi.

Murellus: Murellus is a tribune who is executed for removing crowns placed on Caesar's statues in Rome.  

Pindarus: Pindarus is a servant of Cassius who reluctantly kills Cassius when Cassius asks him to do so, and then flees the scene.

Popilius Lena: Popilius Lena is a Roman senator who speaks to Caesar shortly before the assassination, prompting Brutus and Cassius to fear that their plot has been discovered.

Portia: Portia is Brutus' wife. She loves her husband and is disturbed by the fact that he is upset but will not confide in her. She fears the worst. After Brutus flees Rome, she commits suicide by swallowing burning coals.

Publius: Publius is a Roman senator who is present when Caesar is assassinated, but is not part of the plot. Brutus reassures him he is safe.

Soothsayer: The soothsayer, a kind of prophet, warns Caesar to beware of the ides of March.

Strato: Strato is a servant of Brutus who holds his master's sword as Brutus runs on to it.

Titinius: Titinius is a friend of Brutus and Cassius and a soldier in their army. When he discovers that Cassius misconstrued a situation on the battlefield involving Titinius, and this resulted in Cassius's death, Titinius is so overcome by grief that he kills himself.

Trebonius: Trebonius is one of the ringleaders in the conspiracy against Caesar. He agrees with Brutus that they should not kill Antony as well.

Volumnius: Volumnius is a friend of Brutus who refuses to kill him when Brutus asks him to do so.