While her husband steered Napa winemakers toward competing with Old World rivals in the 1970s, Swiss-born Margrit launched the Great Chefs programme at the Robert Mondavi Winery, helping make California a culinary trend-setter.
She also turned the winery into Napa Valley's cultural centre, bringing sophistication to a sleepy farm area.
Mondavi, 81, speaks about her career and life with her 94-year old husband who is now confined to a wheelchair and unable to speak although doctors have not been able to pinpoint the cause.
Q: How important for the development of Mondavi wines was the work on appreciation for cuisine?
A: "Bob always said, 'We've got it all (in California), the ocean for fish and seafood, the grains, the meat, so let's put it together... The table was always so important to Bob."
Q: Would Mondavi wines have gone as far without an association to fine food and more broadly the 'good life?'
A: "For the first 27 years we never did advertising so of course anything that we did that brought that feeling of wine, food and the arts together was very important... It was our way to show the wines to the world."
Q: What was the Napa Valley like before Mondavi's emphasis on producing quality wines?
A: "The valley still suffered from the aftermath of Prohibition ... We had 21 wineries in 1966 when Bob opened (the Robert Mondavi Winery). Now we have over 400. We have proven we can make wines that Bob said could equal any of the great wines of the world. He never said better. He said equal."
Q: Do you think the growth of Mondavi into a publicly traded company put profits ahead of making fine wine?
A: "It never distracted us. We kept making better wines. That was our goal... Bob always said if you're on a quest for excellence don't worry about anything else."
Q: What is your favourite Mondavi wine?
A: "If I had to go to a desert island with a book and one bottle of wine it would be a cabernet sauvignon."
Q: How will Robert Mondavi be remembered within Napa Valley?
A: "He had time for everybody... If they needed a truck, to crush grapes, three cases of glasses, Bob was always there."