After joining his family’s wine business Thomas Hardy & Sons in 1975, Geoff completed his diploma in wine production two years later in 1977.

In 1980, Geoff and fellow viticulturist Ian Leask purchased a vineyard in McLaren Vale. A few years later, Geoff found the perfect location for producing cool climate grapes in the Adelaide Hills. He planted the vineyard in 1987 and named it K1 since this unique site was the first commercial planting of vines in the Kuitpo region in the southern Adelaide Hills. Since then Geoff has been involved in the planting of more than 3,000 hectares of vines and has consulted to more than 200 different vineyards in Australia, France and Italy.

In 2004, Geoff launched the Hand Crafted by Geoff Hardy and GMH ranges of wine, and then acquired the remaining share of Pertaringa in 2011 (Peratringa since transitioned to Geoff's eldest child Bec in 2020). Together with K1 Wines, these brands now make up Wines by Geoff Hardy and continue the 160-year old family tradition of pushing the boundaries of Australian viticulture.