Walt Disney Studios chairman Dick Cook has stepped down from his post to pursue "new adventures" after privately telling staff he felt he no longer fit in at the No. 1 US entertainment company, said a source.

Cook, who fondly described his 38-year rise from Disneyland ride operator to head the Hollywood studio in 2002, said in a statement that he had been contemplating his departure "for some time now" and felt it was the right time to move on.

Cook, 59, told his staff on Friday that he felt like "a square peg in a round hole," according to a source familiar with Cook's statement. The source did not elaborate.

His departure was not the result of a conflict with chief executive Bob Iger or the company's corporate side, the source said. A Disney Studios spokeswoman said the division was not ready to announce a successor.

The studios division struggled in recent quarters with a slide in DVD sales due to the recession and changing technology and a spate of unprofitable films.

After taking over as CEO in 2005, Iger cut the studios' staff by 20 per cent and refocused the division on a smaller slate of high-concept family-oriented franchises.

The strategy worked for a couple of years - producing megahits like "Pirates of the Caribbean," "National Treasure" and "The Chronicles of Narnia" - but the studio has been slow to cut costs and leverage hits from other divisions.

The respected industry figure left days after he said at a glittering Disney exposition in Anaheim, California that the studios' upcoming slate of films was "the best in our history."

Cook presided over the integration of Pixar Animation Studio, the "Pirates" franchise that went on to gross more than $2 billion at worldwide box offices, and a roster of "big event" films and technological innovations.

Under his watch, Disney became the first studio to push digital 3D technology with "Chicken Little" and got top directors to make 3D to revitalize an industry that was losing ground to video games, piracy and digital home entertainment systems.

In a statement, Iger praised Cook's "outstanding creative instincts and incomparable showmanship."

His departure coincides with Disney's efforts to absorb Marvel Entertainment, whose creative and production staff likely will function independently from Disney as has Pixar's team.-Reuters