Kate Hardcastle is the daughter of wealthy landowner Richard Hardcastle. She is a beautiful, intelligent, witty, and resourceful lead character in the play. When her father mentions Charles Marlow, the son of a wealthy friend, as a possible husband for her, Kate is willing to consider the possibility.

Kate learns about Marlow's tongue-tied shyness or reserve around woman, and it worries her. She notes, "A reserved lover, it is said, always makes a suspicious husband," but then, she weighs the pros and cons of who he is:

Sensible, good-natured; I like all that. But then reserved, and sheepish, that's much against him. Yet can't he be cured of his timidity, by being taught to be proud of his wife?

When Marlow, deceived into thinking her country estate is an inn, sees Kate in the kind of old-fashioned dress her father likes her to wear, he mistakes her for a servant. Bright and quick-thinking, Kate decides to take advantage of the mistake by pretending to be a barmaid—stooping to conquer—and getting to know Marlow for who he is really is. She realizes Marlow is open and at ease with lower-class women in a way that he is not with the upper-class ladies he feels pressure to impress.

Kate, a character often compared to such resourceful, witty, and self-confident characters from Shakespeare as Rosalind from As You Like It and Portia, from The Merchant of Venice, has an opportunity not open to many women of her class, which is to really get to know her prospective husband before she marries him—not to mention the chance to test if her prospective husband really loves her for herself, not her money.

Kate is a good balance between a self-possessed woman who wants to guide her own destiny and a daughter attentive to her father's ideas and respectful of him, making her an exemplary character for her time period.