Billy Bob Thornton
Before he was Bad Santa, and before he was Mr. Angelina Jolie with a vial of her blood around his neck, Billy Bob Thornton was basically nobody. Born in 1955, he took bit parts on TV and in movies throughout the late 80s and early 90s.
During that time, though, he created the character of Karl Childers, a mentally challenged man with a limp, a unique voice, and a murderous past. He performed the character in a one-man show and in a 29-minute short film co-starring Molly Ringwald called Some Folks Call It a Sling Blade.
In 1992, Thornton co-starred with John Ritter, Markie Post, and Aunt Zelda from Sabrina, the Teenage Witch on the short-lived sitcom Hearts Afire. It was while working on that sitcom that he developed his short film into a feature-length presentation, with Ritter in mind for the key role of Vaughan.
Thornton convinced The Shooting Gallery to produce his film for only $1 million, calling them "the hobos—in the best sense of the word—of the business" (source). From there, the rest is history, the true rags-to-riches-to-Angelina-Jolie's-blood-in-a-bottle kind of story that America is made of.