Director Franco Zeffirelli reportedly wanted Mel Gibson for the title role after seeing his near-suicide scene in Lethal Weapon (1987).
Mel Gibson founded his production company "Icon Productions" to raise the financing for this movie, as no major studio wanted to back a Shakespearean movie.
Glenn Close, who plays Gertrude, Hamlet's mother, is only nine years older than Mel Gibson, who plays her on-screen son. This actually represents an improvement over the age difference between the actor and actress playing Hamlet and Gertrude in Hamlet (1948), in which Sir Laurence Olivier (Hamlet) was almost eleven years older than Eileen Herlie, who played Gertrude.
This was the first Shakespearean role that Glenn Close had ever attempted on either stage or screen.
Mel Gibson's only previous Shakespeare experience was playing Juliet in an all male production of "Romeo and Juliet" in Australia. By contrast, Sir Alan Bates (who played Claudius) had played Hamlet in London in 1970 and Paul Scofield (who played the Ghost) had played the part in 1948 and 1955, and is considered one of the greatest twentieth century interpreters of the role.