Roy E. Disney, bearer of the Disney family torch and occasional bane of the entertainment conglomerate's chief executives, died Wednesday at age 79 following a year-long battle with stomach cancer.

A nephew of, and near dead-ringer for, Walt Disney, Roy spent 56 years at the company his uncle founded, working as a writer, director, producer and head of Disney's (DIS) animation department, and serving as its vice chairman. But it was as an activist shareholder that Disney had the most profound impact. Disney was instrumental in forcing out CEO Ronald William Miller, Walt Disney's son-in-law, in 1984, and replacing him with Michael Eisner.

But after a period of harmony in the 1990s -- during which time the studio produced such hits as The Lion King and The Little Mermaid -- the relationship between the two men soured. Disney felt that Eisner had neglected the company's theme-park business and failed to appreciate the value of Pixar, the computer-animation film studio. Disney decided to throw his invaluable name and billion-dollar stake in the company into a bid to unseat Eisner. The effort succeeded, and in 2005 Eisner resigned.

Disney died at Hoag Memorial Hospital in Newport Beach, Calif.