Olav Thon bought his first building in 1951 and opened his first restaurant in 1966. His company owns a total of 450 properties in Norway, including shopping malls, office buildings, Retail stores, and hotels. His principal holdings are the private companies Stormgård AS and Thongård AS, in addition to a major stake in the publicly traded company Olav Thon Eiendomsselskap ASA.
In an article in the Norwegian newspaper Dagens Næringsliv on September 10, 2008, Olav Thon's solicitor, John Christian Elden, announced that Olav Thon intends to give away his entire fortune through the establishment of an independent foundation that focuses on the medical sciences. On December 10, 2013, he announced the decision for the entire 71.9% stake in his real estate company Olav Thon Eiendomsselskap ASA to give for charity trust of his own. Therefore, later, in February 2014, his personal assets estimated around 1 billion USD.
Thon was appointed honorary doctorate at Karlstad University in 2013.