The five most important characters in Hamlet are Prince Hamlet, the Ghost of King Hamlet, Queen Gertrude, King Claudius and Laertes. Of these, Laertes is the most arguable, and many readers would certainly choose Ophelia, Polonius or Horatio instead. The textual rationale for choosing these five characters, however, is simple. They allow the central plot of Hamlet, without subplots, to take place.

Hamlet is grieving for his father's death and is also somewhat suspicious that foul play was involved. The ghost confirms this suspicion, telling him that Claudius murdered King Hamlet in order to steal his crown and marry Gertrude. Hamlet, after some prevarication, resolves to kill Claudius. Claudius, aware that his life is in danger, sets Laertes against Hamlet, and the two fight. In the final scene, Claudius, Gertrude, Laertes and Hamlet are all killed. This means that one of the most important characters was dead before the play began, and the other four die at the very end.

If one were staging a highly abbreviated version of Hamlet, therefore, these are the five characters one would require. Perhaps the weakest point is that Laertes would have no obvious quarrel with Hamlet if he had not been responsible for the deaths of Polonius and Ophelia. Claudius, however, could presumably make something up, perhaps involving these characters who could be referred to without appearing onstage. In any case, the alternative would be for the cowardly Claudius to face Hamlet himself, which seems unlikely.

The single most important character in Shakespeare's Hamlet is the eponymous protagonist, Hamlet himself. He has the most lines of any character in the play and the plot revolves around his actions and decisions. He is a complex character whose personality and decisions change over the course of the play and he has among the most impressive and quoted soliloquies in drama, including "To be or not to be ..." in "nunnery scene" of act 3.

Claudius, the new King of Denmark, is Hamlet's antagonist in the play. As the primary antagonist, he is normally considered second in importance to Hamlet himself, and is a perennial favorite with actors and audiences. His actions in killing Hamlet's father (his own brother) and marrying Hamlet's mother Gertrude set the events of the play in action. He is a complex "smiling villain" who is important in that rather being just a narrow stereotype of evil is instead charming and intelligent with a degree of moral complexity.

Of the remaining characters, many can be ranked as the next three in importance. Ophelia is Hamlet's love interest and is central as such. Her character has several important speeches and helps advance the plot. The scene in act 3 where Hamlet tells Ophelia "get thee to a nunnery" is important in developing the feigned madness plot. Ophelia also has a striking mad scene in act 4, including the line "There’s rosemary, that’s for remembrance..." This is one of the most memorable scenes and female roles in Shakespeare.

Gertrude as Hamlet's mother is an important element in the plot, although her character is less well developed than others in the play. Another important character, and one whose murder by Hamlet is a significant plot element, is the unsympathetic Polonius. One could also choose Hamlet's friend Horatio as an important character or the, at times comic, duo of Rosencrantz and Guildenstern.