Diemersfontein has belonged to the Sonnenberg family since the early 1940s, when David's grandfather, Max, bought the 183 hectare farm, which lies in the shadow of the majestic Hawekwa Mountains with a panoramic view of both Du Toit's Kloof and Bains' Kloof.

Central to the working wine estate, is the third-generation family manor house, known as the 'Groot Huis', overlooking magnificent gardens, which are reminiscent of an era when gracious living and tranquility were the order of the day. Designed by Cecilia Sonnenberg, the gardens offer an abundance of roses and azaleas, a secluded swimming pool and is a much sought after venue for weddings, important celebrations and a peaceful getaway destination for conferences.
Max Sonnenberg, with his son Richard (Dick), was the co-founder of Woolworths South Africa and a Member of Parliament in the Jan Smuts Government. He and his family used Diemersfontein as a country retreat, and during the war years, Italian prisoners of war were housed in the farm cottages.
Richard took over the farm in the 1950s and became more involved in the farming operations. His wife Cecilia, a well known Cape Town actress and producer, was the co-founder of Maynardville Open Air Theatre, famous for its Shakespearian productions.
The farm's association with the arts started with the strains of opera singing drifting up from the cottages housing the Italian prisoners. The family tradition of being patrons and contributors to the arts has been followed by the present owners, David and Sue Sonnenberg and Sue, an artist and chorister, is involved with encouraging and sponsoring local artists, providing them with materials and a place to work.

The first vineyards were planted by David's father in the 1970s, and in 2000 David built his own cellar and started producing award-winning estate wines. Vineyard plantings include Shiraz, Pinotage, Cabernet Sauvignon, Merlot and also the "lesser known" varietals Viognier, Barbera, Roobernet and Mouvedre. Diemersfontein's maiden vintage (2001) won the Paul Sauer Trophy for a wooded Pinotage at the SA Young Wine Show and from that first vintage, awards have continued to be received by the Estate for many of their wines.
Some sections of the Estate are now offered for country living for those who favour a wine farm lifestyle, with all the advantages and none of the responsibilities. All the smallholdings, courtyard and fynbos mountain view sites are positioned in and around the vineyards to offer owners panoramic views, a secure environment and sophisticated infrastructure, while losing nothing of the tradition and authenticity that is Diemersfontein Wine and Country Estate.