Initially, Miller came on board as part of the original Disneyland team (he was employee no. 6), and then served as second assistant on the studio’s 1957 live-action feature Old Yeller. He spent years as an assistant director and producer on the studio’s live-action projects, including tv series like Zorro and The Magical World of Disney, and films such as Son of Flubber, That Darn Cat!, The Shaggy D.A., and Herbie Goes to Monte Carlo.

Miller eventually moved into management, and was named executive vice president in charge of production and creative affairs in 1976. By 1983, Miller served as both president and CEO of the Walt Disney Company. His reign as CEO was shortlived as he was infamously forced out in 1984 by Roy E. Disney and replaced by Michael Eisner and Frank Wells, a pivotal moment in the company’s history that transformed it from a family-run enterprise into a global media conglomerate.

Miller presided over a tumultuous era in the company’s history as many of the studio’s key figures were retiring, while younger employees were disgruntled with the company’s direction. One of Miller’s key challenges was the mass resignation of Don Bluth and 10 other animators in 1979, reducing the company’s animation staff by 15% and delaying the completion of The Fox and the Hound.

Though he was often derided by artists for lacking creative skill, Miller managed to set up a framework for the company’s resurgence in the late 1980s. During his tenure, he established profitable divisions such as Walt Disney Home Video, The Disney Channel, and Touchstone Pictures. Miller also approved the funding for Disney’s first foray into New York theater, backing the first workshop for a show that eventually would open on Broadway.

Speaking to a reporter recently about why he wanted to launch Touchstone, the mature film label that helped Disney shake off its reputation as a chilren’s entertainment company, Miller shared this memory:

“I watched the frustration with Walt, the fact that he had cornered himself by being a G-rated company while all these other companies are making…films dealing with sex and things like that. We had tunnel vision and we could not break apart from that. One day, Walt called and said ‘I’ve got a film I’m running tonight, why don’t you come on over?’ So Diane and I, we went over there. The film was To Kill a Mockingbird. When it was over Walt said, ‘Damn, I wish I could make a film like that.’ But he couldn’t.”

Under Miller, the company also released Tron, which featured the trailblazing use of computer-generated imagery in a live-action feature, and it also starting developing Who Framed Roger Rabbit, which became a box office phenomenon when it was finally completed in 1988.

On Miller’s passing, former Disney CEO Michael Eisner remembered him as a “serious good guy.” Current Walt Disney Company CEO Bob Iger also shared his condolences and admiration for Miller’s accomplishments on Twitter:

Few people had Ron’s understanding of our history, or a deeper appreciation and respect for our company. I was fortunate to have known him, and even luckier to have called him a friend. My thoughts and prayers are with his family. — Robert Iger (@RobertIger) February 10, 2019

After leaving Disney in 1984, Miller moved to northern California where he established Silverado Vineyards with Diane and her mother, Lillian Disney. He almost never granted interviews and only spoke publicly about his Disney career in support of Diane’s projects, such as the 2001 documentary Walt: The Man Behind the Myth.

According to his official bio, Miller believed that establishing the Walt Disney Family Museum was necessary since he was “discouraged that Walt Disney’s name had become a corporate ‘brand,’ and that the identity of the man himself had become obscured.”

Miller is survived by his children Christopher Miller, Joanna Miller, Tamara Diane Miller, Jennifer Goff, Walter Elias Disney Miller, Ronald Miller, and Patrick Miller; grandchildren Annabelle Rey, Nicholas Runeare, Ryan Scheer, Danielle Durham, Sam Goff, Lily Goff, Charlotte Goff, Sebastian Runeare, Haley Scheer, Reilly Miller, Madeline Goff, William Miller, and Elias Miller; and great-grandchildren Stella Durham, Finley Scheer, and Evelyn and Mason Goff.

Services will be held privately. The museum will announce a public commemoration of Miller’s life and career at a later date.