The award is considered a major prize on the film festival circuit, and could help the movie secure a distribution deal.
Hamill is portrayed in the film by Russell Harvard, and the film is directed by Oren Kaplan.
The movie follows Hamill's early days dealing with deafness as well as the genesis of his wrestling career. It stops short of his pro fighting career.
The 34-year-old Hamill shot to fame on the third season of The Ultimate Fighter, where his compelling story made him a fan favorite. He's 10-2 overall, and in the midst of a five fight win streak, most recently defeating Tito Ortiz at UFC 121 on Oct. 23.
The Breakthrough Award is voted upon by Film Fest audiences via balloting after film screenings.
The award has not been the only recognition received by the film, which was also listed as a "Hidden Gem" by the Los Angeles Times prior to the Festival.