"I no longer believe the chairman role is the right professional fit for me."
Iger wished him well in a statement.
"Rich Ross's creative instincts, business acumen and personal integrity have driven results in key businesses for Disney," Iger said. "I appreciate his countless contributions throughout his entire career."
Ross's resignation is effective immediately. Disney did not name a successor.
A couple possible candidates for elevation at the studio are John Lasseter and Ed Catmull, who together built Pixar from a computer imaging company into an animated movie powerhouse. After Disney's acquisition in 2006, the men have top jobs overseeing animated movies at Pixar and Disney.
The men have helped Disney's animated films move "in the right direction," according to Don Peri, the author of a couple books on Disney animators including "Working with Disney." He declined to speculate on whether they would make good studio heads.
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