1. Robin Williams’ last line in the film was ad-libbed.
Williams had read Will’s note a few times, saying a different line each take. This was obviously the keeper.
2. And the whole “farting wife” scene was unscripted.
That Matt Damon laugh is as genuine as it comes. In the original script, Sean tells Will a story about how his wife used to turn an alarm clock off in her sleep.
3. The role of Skylar was based on Matt Damon’s ex-girlfriend Skylar Satenstein, whom he met at Harvard.
Before filming began, Satenstein left Damon for Metallica drummer Lars Ulrich.
4. Matt Damon and Minnie Driver dated during production, but their romance eventually came to a very rocky end.
Minnie Driver told The Telegraph, “We split up very publicly that April, which was grim, and it turned from this beautiful thing into something so dark. I’m always really sad that we didn’t stay friends because it was absolutely incandescent making that film.”
5. The character of Sean is based on a combination of Matt Damon’s mom and Ben Affleck’s dad.
According to Boston Magazine, when Robin Williams read the script, he said, “This is really extraordinary.” He was so interested in Sean, he asked where the inspiration came from and found out it was based on their parents.
6. Minnie Driver almost didn’t get the part of Skylar.
Producer Harvey Weinstein didn’t think she was sexy and cute enough for the role, but he eventually backed down because Damon and Affleck wanted her so much.
7. Chuckie takes Will’s place at a meeting with a company called Holden & McNeil. Holden McNeil was the name of Ben Affleck’s character in Chasing Amy.
The company was originally supposed to be Tri-Tech Laboratories.
8. The picture of the boat in Sean’s office was actually painted by director Gus Van Sant.
You can see more of his artwork here.
9. The script for Good Will Hunting started as a class assignment.
He was supposed to write a one-act play, but he wrote a 40-page partial movie script instead. When he moved to L.A., he asked Ben Affleck to help him make it into something bigger.
10. Matt Damon and Ben Affleck used to slip Sean and Will sex scenes into the script.
They had creative differences with Castle Rock, and they felt the production company wasn’t reading any of their rewrites, so they did a test and inserted erotic scenes. Castle Rock never noticed, and the guys eventually got Miramax to buy rights.
Here’s an example: “Sean talks to Will and unloads his conscience. Will takes a moment and then gives Sean a soulful look and leans in and starts blowing him.”
11. Damon really liked his ’90s frosted tips (at the time).
Matt Damon told Vulture: “For whatever weird reason, at that age, I loved that haircut. Gus was like, ‘Really?’ Ben was like, ‘Really?’ If you look at Ben’s hair in that movie, it’s totally acceptable by today’s standards, but no, I wanted the frosted fuckin’ hair. I don’t know what my problem was. I looked like I should be singing backup for Color Me Badd.”
12. Casey Affleck ad-libbed a bunch of his lines.
This particular one (pictured above) was in the script, though.
13. Damon and Affleck cried the first day of filming.
It was during a scene with Stellan Skarsgard and Robin Williams.
Damon said, “When Gus called action and we watched these guys — I mean accomplished actors — do our scene verbatim, we had waited so long for this to happen. I remember just sitting next to Ben and I had tears rolling down my cheeks because I was just so happy and relieved that it was really happening.
14. Good Will Hunting is Matt Damon’s favorite movie he’s done.
Mainly because it took so long and he wrote it.
15. And last but not least, this movie is 16 YEARS OLD.
Just let that sink in.