Willem Oppenoorth mainly painted many landscapes. From rivers, dunes, heaths, polders to the sea and the beach. Oppenoorth was born in Amsterdam, but was educated at the academy in Antwerp. He then lived and worked in his hometown, but also in The Hague and in Gelderland and Overijssel. Oppenoorth was a member of Arti et Amicitiae and a board member of Pulchri.