Hamlet
The son of Old Hamlet and Gertrude, thus Prince of Denmark. The ghost of Old Hamlet charges him with the task of killing his uncle, Claudius, for killing him and usurping the throne of Denmark. Hamlet is a moody, theatrical, witty, brilliant young man, perpetually fascinated and tormented by doubts and introspection. It is famously difficult to pin down his true thoughts and feelings -- does he love Ophelia, and does he really intend to kill Claudius? In fact, it often seems as though Hamlet pursues lines of thought and emotion merely for their experimental value, testing this or that idea without any interest in applying his resolutions in the practical world. The variety of his moods, from manic to somber, seems to cover much of the range of human possibility.
Old Hamlet
The former King of Denmark. Old Hamlet appears as a ghost and exhorts his son to kill Claudius, whom he claims has killed him in order to secure the throne and the queen of Denmark. Hamlet fears (or at least says he fears) that the ghost is an imposter, an evil spirit sent to lure him to hell. Old Hamlet's ghost reappears in Act Three of the play when Hamlet goes too far in berating his mother. After this second appearance, we hear and see no more of him.
Claudius
Old Hamlet's brother, Hamlet's uncle, and Gertrude's newlywed husband. He murdered his brother in order to seize the throne and subsequently married Gertrude, his erstwhile sister-in-law. Claudius appears to be a rather dull man who is fond of the pleasures of the flesh, sex and drinking. Only as the play goes on do we become certain that he is indeed guilty of murder and usurpation. Claudius is the only character aside from Hamlet to have a soliloquy in the play. When he is convinced that Hamlet has found him out, Claudius eventually schemes to have his nephew-cum-son murdered.
Gertrude
Old Hamlet's widow and Claudius' wife. She seems unaware that Claudius killed her former husband. Gertrude loves Hamlet tremendously, while Hamlet has very mixed feelings about her for marrying the (in his eyes) inferior Claudius after her first husband's death. Hamlet attributes this need for a husband to her lustiness. Gertrude figures prominently in many of the major scenes in the play, including the killing of Polonius and the death of Ophelia.
Horatio
Hamlet's closest friend. They know each other from the University of Wittenberg, where they are both students. Horatio is presented as a studious, skeptical young man, perhaps more serious and less ingenious than Hamlet but more than capable of trading witticisms with his good friend. In a moving tribute just before the play-within-the-play begins, in Act Two scene two, Hamlet praises Horatio as his soul's choice and declares that he loves Horatio because he is "not passion's slave" but is rather good-humored and philosophical through all of life's buffets. At the end of the play, Hamlet charges Horatio with the task of explaining the pile of bodies to the confused onlookers in court.
Polonius
The father of Ophelia and Laertes and the chief adviser to the throne of Denmark. Polonius is a windy, pedantic, interfering, suspicious, silly old man, a "rash, intruding fool," in Hamlet's phrase. Polonius is forever fomenting intrigue and hiding behind tapestries to spy. He hatches the theory that Ophelia caused Hamlet to go mad by rejecting him. Polonius' demise is fitting to his flaws. Hamlet accidentally kills the old man while he eavesdrops behind an arras in Gertrude's bedroom. Polonius' death causes his daughter to go mad.
Ophelia
The daughter of Polonius and sister of Laertes. Ophelia has received several tributes of love from Hamlet but rejects him after her father orders her to do so. In general, Ophelia is controlled by the men in her life, moved around like a pawn in their scheme to discover Hamlet's distemper. Moreover, Ophelia is regularly mocked by Hamlet and lectured by her father and brother about her sexuality. She goes mad after Hamlet murders Polonius. She later drowns.
Laertes
Polonius' son and Ophelia's brother. Laertes is an impetuous young man who lives primarily in Paris, France. We see him at the beginning of the play at the celebration of Claudius and Gertrude's wedding. He then returns to Paris, only to return in Act Four with an angry entourage after his father's death at Hamlet's hands. He and Claudius conspire to kill Hamlet in the course of a duel between Laertes and the prince.
Rosencrantz and Guildenstern
Friends of Hamlet's from the University of Wittenberg. Claudius invites them to court in order to spy on Hamlet. Rosencrantz and Guildenstern are often treated as comic relief; they are sycophantic, vaguely absurd fellows. After Hamlet kills Polonius, Rosencrantz and Guildenstern are assigned to accompany Hamlet to England. They carry a letter from Claudius asking the English king to kill Hamlet upon his arrival. Hamlet discovers this plot and alters the letter so that Rosencrantz and Guildenstern are put to death instead. We learn that they have indeed been executed at the very close of the play.
Fortinbras
The Prince of Norway. In many ways his story is parallel to Hamlet's: he too has lost his father by violence (Old Hamlet killed Old Fortinbras in single combat); he too is impeded from ascending the throne by an interfering uncle. But despite their biographical similarities, Fortinbras and Hamlet are constitutional opposites. Where Hamlet is pensive and mercurial, Fortinbras is all action. He leads an army through Denmark in order to attack disputed territory in Poland. At the end of the play, and with Hamlet's dying assent, Fortinbras assumes the crown of Denmark.
Osric
The ludicrous, flowery, stupid courtier who invites Hamlet to fence with Laertes, then serves as referee during the contest.
The gravediggers
Two "clowns" (roles played by comic actors), a principal gravedigger and his assistant. They figure only in one scene -- Act Five scene one -- yet never fail to make a big impression on readers and audience members. The primary gravedigger is a very witty man, macabre and intelligent, who is the only character in the play capable of trading barbs with Hamlet. They are the only speaking representatives of the lower classes in the play and their perspective is a remarkable contrast to that of the nobles.
The players
A group of (presumably English) actors who arrive in Denmark. Hamlet knows this company well and listens, enraptured, while the chief player recites a long speech about the death of Priam and the wrath of Hecuba. Hamlet uses the players to stage an adaptation of "The Death of Gonzago" which he calls "The Mousetrap" -- a play that reprises almost perfectly the account of Old Hamlet's death as told by the ghost -- in order to be sure of Claudius' guilt.
A Priest
Charged with performing the rites at Ophelia's funeral. Because of the doubtful circumstances of Ophelia's death, the priest refuses to do more than the bare minimum as she is interred.
Reynaldo
Polonius' servant, sent to check on Laertes in Paris. He receives absurdly detailed instructions in espionage from his master.
Bernardo
A soldier who is among the first to see the ghost of Old Hamlet.
Marcellus
A soldier who is among the first to see the ghost of Old Hamlet.
Francisco
A soldier.
Voltemand
A courtier.
Cornelius
A courtier.
A Captain
A captain in Fortinbras' army who speaks briefly with Hamlet.
Ambassadors
Ambassadors from England who arrive at the play's close to announce that Rosencrantz and Guildenstern are dead.