She founded Duckhorn Vineyards with her husband in 1976 and made their first Napa Valley Merlot and Cabernet Sauvignon in 1978.  At the time, many Napa Valley wineries were using Merlot as a blending grape, but Margaret and Dan Duckhorn believed that this elegant varietal was underappreciated in North America and championed its potential in California as a great standalone wine. This decision ultimately established Merlot as one of the New World’s most popular and respected varietal wines.

Raised in a military family, she was a graduate of what is now University of Maryland Global Campus. she became interested in wine after being exposed to the Mosel region's distinctive wine while studying at UMGC's Munich, Germany, campus.

From the beginning, Margaret took an extremely active role in the day-to-day operations of the winery, hand sorting the fruit and working alongside winemaker Tom Rinaldi during blending. Later, Margaret began specializing in marketing and international public relations, becoming a strong voice for Duckhorn Vineyards, and a champion for the Napa Valley winegrowing community.

Over the years, Margaret also helped to define Duckhorn Vineyards’ philosophy and core set of values. “This valley is our home,” she once said. “We live here. Our children live here. We recognize the importance of taking care of this remarkable place, and of giving back to the community that has given us so much.”  

Services will be private.  In lieu of flowers, the family suggests donations to the Napa Valley Community Foundation.