Miller founded the Walt Disney Family Museum, which opened in 2009 in San Francisco's Presidio, as a tribute to her family's legacy. One of her major concerns was that her father's name had become associated more with a corporate identity than with the man himself.
She also played a key role in the completion of the Frank Gehry-designed Walt Disney Concert Hall in Los Angeles, a project started with a $50 million gift from her mother.
In 1997, she bucked project leaders like Richard Riordan, the mayor at the time, and the billionaire Eli Broad, who said Gehry's firm lacked the experience to execute the plans for the building's unusual curved polished steel design. At a crucial point, Miller threatened to withhold the roughly $20 million remaining of her mother's gift if Gehry was not kept on.
"I wanted something that would bear my father's name, that would come from his wealth but not be commercial," Miller told the Los Angeles Times in September. "I think we achieved that."
Miller's younger sister, Sharon, died of cancer in 1993. She is survived by her husband, Ronald, who owns the Silverado Vineyards Winery in Napa Valley, as well as seven children and 13 grandchildren.