After working at a number of wineries in the Napa Valley — including Souverain Winery, Christian Brothers Cellars, Beaulieu Vineyard (working alongside André Tchelistcheff), and Robert Mondavi — Grgich became the winemaker and limited partner at Chateau Montelena. His 1973 vintage Chardonnay was selected to compete in the historic Paris Wine Tasting of 1976, where it was ranked the number one white wine. A dramatized version of the story is told in the 2008 film "Bottle Shock" which did not depict Grgich because "he did not want to be part of it."