Bill Mechanic, the veteran chairman of Fox Filmed Entertainment who backed Titanic, has quit.
Mechanic resigned late on Thursday to form his own movie production company.
"The studio is in excellent shape with a strong summer line-up and terrific product into next summer, and so I feel now is the time to pursue other personal ambitions," Mechanic said.
Mechanic, who had been at Fox for seven years, has yet to name his new, independent production outfit and declined to discuss his plans further. Mechanic's contract with Fox ended this autumn. President Peter Chernin said the company expects to name a successor "in the weeks ahead".
"While we are sorry to see him go, we respect his desire to tackle new endeavors in an industry that is constantly changing," Chernin said.
Amongst Fox's successes while mechanic was at the studio are Braveheart and Titanic, the film industry's most expensive movie at around $200m and the industry's biggest blockbuster with $1.8 billion worldwide. Fox also released Star Wars: The Phantom Menace, although director-producer George Lucas made the film and saw the lion's share of profits.
After about 16 years of senior film studio management, Mechanic said it was time that he found his own "creative freedom" in the movie business. "I came to Fox seven years ago with the idea of building a stable, vibrant company and I am satisfied that I have fulfilled those goals." he said.