The 68-year-old actor received an honourary doctorate of fine arts at Bates College in Maine yesterday and joked that leaving school early to pursue a movie career had been the best thing he could have done financially.
He said: "In many ways, leaving school when I did it was an advantage. I saved nearly $8000 by not having to pay tuition and expenses for four years of education."
"I feel a little foolish, because if I had waited until now not to go to college, I could have saved around a quarter of a million."
"It worked out just fine. I saved the money, and I got the degree."
The Raging Bull star also advised the assembled guests to follow his career path as his life "sucked" before he became a film star.
Referring to fellow honorees, he joked: "With all due respect to Gwen Ifill and Bonnie Bassler, I think this is the most important piece of advice you'll get today; become a movie star."
"Now, you might be tempted by other careers, other interests, other commitments. There might be pressure on you to change the world, but you want to find the strength to resist."
"When I started, I wasn't a movie star, and it sucked. The moment I became a movie star, things started to get better."
And the actor admitted his mother would have been proud to see him receive a degree - but claimed she would rather it had been from a more prestigious establishment.
He said: "My mother would be so proud to see her son, who never graduated high school, standing up here, receiving this honourary doctorate of fine arts. She would've been more proud of it if it was [from] Harvard."