William Hamilton was an Irish stage actor of the eighteenth century. He was the son of the actress Sarah Hamilton. His aunt was the actress Anna Marcella Giffard. Along with his brother James, he first appeared on stage in January 1735 at the Goodman's Fields Theatre in London as a child actor. They continued to appear together in London at the Lincoln's Inn Fields Theatre and Theatre Royal, Drury Lane until 1739 when they returned with their parents to Dublin and worked at the Smock Alley Theatre.