Born and raised in the Congo, the early influence of African mask’s and mystical tribal traditions have deeply penetrated Van Mullem’s life work. His portraits fall into the invisible territory that affects the outer human experience, while he inquisitively explores the forces underlying physical existence. Van Mullem ventures into the delicate territory where humans portray themselves in culture (wear their masks) and make attempts to reach behind the veil, painting and giving life to the unseen, yet, powerful forces of the universal human experience; the eternal soul. Most people see only their physical reality in day to day life but rarely reach inside of themselves and reflect upon those "states of being which influence the totality of life". Van Mullem’s work brings the viewer directly into sight of the hidden forces within, giving his viewer a physical figure to these unseeable electric forces such as emotions, thoughts, feelings and desires that vigorously drive both individuals as well as societies, in every millisecond of universal existence.
The artist is recognised for his luminous brushstrokes of oil-based ink on board and canvas. The almost faceless yet identifiable figures that emerge from the paintings have led his work to be compared to Francis Bacon, Glenn Brown, Goya and Vermeer, though his works are drawn completely from his own emotional content and experience. Van Mullen's portraits form a more sensuous approach to typical portraiture through the exploitation of muted swirling tones. As a result, his portraits are not necessarily of himself but portray his own thoughts, personality, desires and impulses. Van Mullen tends to work with oil-based inks on top of wooden boards, forming the loose and natural backgrounds in his portraits. By applying his own thoughts onto his fictional subjects, he aims to explore the human ability to adapt and evolve.
Van Mullem’s work can be found in public and private collections internationally, including collections in Brussels, London, Dubai, Abu Dhabi, Los Angeles and at the Musee d’Ixelles in Belgium. He has most recently exhibited at Museum at Ciurlionis National Museum in Lithuania and Musée d’Art Classique Mougins in France.