Hale is an interesting and well developed character. He serves the dramatic function of an outsider. He shows towards the end of the play that the ministry and the courts need not all be evil, but it is possible to realise the errors of one's ways and fix their effects.
Hale is also used to contrast the fear and hysteria that overwhelms the rest of Salem. In Act I, Hale says that the ways "of the Devil are precise." Hale is looking past the superstition, and avoided the panic. Hale is the voice of reason throughout. When he realizes that the courts no longer care about truth, he pleads with the accused to tell lies in order to be freed.
He functions as a contrast to Parris and Danforth; he is essentially a authority that is able to see the hysteria for what is really is. The ignorance of the court and how it takes theorcracy to an extent wherby the least sign of neglecting religion is associated with the Devil's work is juxtaposed to Hale's logic and personal morals.