Originally, the estate was an integral part of the Sonian Forest. In 1833, Marquis Maximilien de Béthune bought 341 ha of forest, which he partially cleared to lay out a park. He built three warden's cottages and two farms, then he began construction on the château (completed in 1842), which he entrusted to the French architect
Jean-Jacques Nicolas Arveuf-Fransquin and to the Belgian Jean-François Coppens.

Erected at the top of the hill, in the Flemish neo-renaissance style then at its height of popularity, the château, dressed in red brick with lines of natural stone was flanked by four towers and four turrets. The marshland at the bottom of the hill was turned into a pond.

From 1871 to 1893, the estate belonged to Baron Antoine de Roest d'Alkemade who extended it southwards to the present boundaries by acquiring the meadows, banks of the Argentine and the Nysdam ponds.

In 1893, the industrialist Ernest Solvay - the founder of global firm "Solvay & Co." - bought the property as his summer residence. He entrusted Victor Horta to revise the interior layout of the château. A front terrace was built with a glass canopy and cast iron columns. Ernest Solvay rearranged the park and expanded the estate further so that in 1920, there were 490 hectares.

While he was alive, Ernest Solvay left his property to his children. The Domaine de La Hulpe was divided between his two sons, the north part going to Edmond and his eldest son Armand received the château and the bottom part of the property, which together make up the current Domaine Solvay.

Armand Solvay, and later his son, Ernest-John made significant alterations to the estate, giving it the layout it has today.

The architect Georges Collin made major changes to the appearance of the château. The turrets, central steeple and the glass canopy were removed; the spires on the towers shortened and the red brick was covered in light-coloured render.

Ernest-John built a belvedere with 140 steps leading up to it. A French garden was created on one side of the château. Opposite the main façade, an opening turfed along 800m in a straight line through the forest culminated in a 36m high obelisk topped by a golden sun. He planted exotic species that are still there to this day.

Concerned by the prospect that in the future the estate would be broken up, he was successful in listing it as a protected building in 1963 and some years later, he decided to gift it to the Belgian state under the condition that it would not be divided and that cultural exchanges and events would be developed.

After Ernest-John died in 1972, this wonderful 227 hectare property became open to the public.