Will Hunting (Matt Damon) is guy from South Boston who is a night janitor at MIT. Lambeau (Stellan Skarsgard) is a math prof at MIT who gives his students an extremely difficult problem to solve. Someone solves it but won't take credit. He gives another one and catches Will solving it, but Will runs off before Lambeau can talk to him. Before he can track him down Will gets arrested. Lambeau arranges his release if he agrees to counseling and to meet with the professor weekly. Lambeau turns to his old college buddy Sean McGuire (Robin Williams), a psychology teacher at a community college, to counsel Will his newly found math genius. But Will does not want help, he would rather live his sheltered life, consisting mainly of drinking with his best friend Chuckie (Ben Affleck). Before long Will and Sean open up to each other. Will also starts a relationship with a Harvard student, Skylar (Minnie Driver). Soon everyone is trying to decide what's best for Will, but only he can make that decision.
This is a well thought out film. The dialogue is great and comes across as authentic. Damon, Affleck, and Williams all give great performances. The interplay between Will and Sean is the best part of the movie. It's almost painful to watch Will be so smart and still act like a dumbass, I guess that's why Good Will Hunting is such an effective movie.