Every American should have a good knowledge of the national Constitution. That's where our rights and laws originate from. It also sets the stage for the state level constitutions.
It depends on WHY you hire one.
Lots of companies ... And even governments ... Hire outside hackers to assess their network security.
But if you attempt to break in to someone else's network or software, without their permission, it is illegal. Basically the electronic version of breaking into someone's house.