Image caption Rich Ross presided over major TV successes Hannah Montana and High School Musical

The head of Disney film-making studio, Rich Ross, has resigned as chairman a month after the film John Carter became one of the company's biggest flops.

He revealed his move by email: "I no longer believe that the chairman role is the right professional fit for me."

A 15-year Disney veteran, he became chairman in 2009.

He was previously the president of the Disney Channel when it created the hugely successful High School Musical and Hannah Montana series.

At the movie division, Mr Ross, 50, approved production of the science fiction film John Carter, although it had been in development before he joined the studio.

The film, which was based on a series of books by Tarzan writer Edgar Rice Burroughs, eventually cost more than $250m (£155m, 189m euros) and last month Disney said it expected the film to lose about $200m.

That would leave the studio with $80m-$210m in operating losses.

Disney is not expected to appoint a new studio chairman immediately.

The company's Chief Executive Bob Iger hailed Mr Ross's contribution: "For more than a decade, Rich Ross' creative instincts, business acumen and personal integrity have driven results in key businesses for Disney.

"I appreciate his countless contributions throughout his entire career at Disney and expect he will have tremendous success in whatever he chooses to do next."

Mr Ross joined the Disney Channel in 1996 as a programming and production executive and was promoted to president of the cable channel in 2004.