Her death Tuesday in Napa was confirmed by The Walt Disney Co. The cause was complications from a fall, said Andi Wang, spokeswoman for the Walt Disney Family Museum.
"As the beloved daughter of Walt Disney and one of his inspirations for creating Disneyland, she holds a special place in the history of The Walt Disney Co. and in the hearts of fans everywhere," Robert A. Iger, the company's president and CEO, said in a statement. "She will be remembered for her grace and generosity and tireless work to preserve her father's legacy."
Miller, the eldest daughter of Walt and Lillian Disney, was born Dec. 18, 1933. In later life, she remembered her father as a man who was caring and patient with his children.
"He'd take me and my sister Sharon to the merry-go-round at Griffith Park and stand there all day waiting until we were ready to go," Miller told the San Francisco Chronicle in 1998. "As he stood there, he kept thinking there should be more for parents and children to do together, and the idea for Disneyland was born."
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 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.