Demarco's work is concerned largely with color and movement. He traveled widely and gave many personal exhibitions of his work, especially between the years 1961 and 1989. Afterward he continued to create work and his work continued to be exhibited, often alongside the work of fellow South Americans Le Parc, Soto, Horacio Garcia Rossi, and Carlos Cruz-Diez.
His work has long been exhibited at Denise René's gallery. Some of his unfinished works are currently undergoing restoration and will soon be made available for purchase and exhibition.