Enrico Castellani studied painting and sculpture at the Académie des Beaux-Arts and architecture at the École Nationale Supérieure in Belgium until 1956. In 1957 Enrico Castellani returned to Italy, where he became acquainted with Italian avant-garde artists Piero Manzoni, Lucio Fontana, Vincenzo Agnetti and Agostino Bonalumi in Milan and came into contact with Yves Klein and the group of German artists known as "ZERO". In 1957-58 the legendary "ZERO" evening exhibitions of work by Heinz Mack, Otto Piene and Günther Uecker were held in Düsseldorf that were to be so influential in Italy as well. In 1958 Enrico Castellani joined the "Movimento Arte Nucleare" group to which Manzoni, Fontana, Picabia and Bonalumi also belonged. Castellani and Manzoni forged firm ties of friendship. In December 1959 the two artists opened Galleria Azimut in Milan. That same December also saw the launch of their journal, "Azimuth". The aims of the Azimut artists were to ensure that art did not imitate; a work was to be entirely self-referential and possess reality and authenticity in its own right. Light and shade, space and structure should be contained in the work itself and not be elicited in viewers by means of sensory deception.
In 1959 Castellani showed his "Superficie Nera" works for the first time. To make them, he worked over his canvases with a nail gun to produce a relief surface that induced light and shade effects through alternating depressions and raised areas. Castellani left the canvases monochrome, usually white. In the 1970s and 1980s, Enrico Castellani also used other materials, including aluminum.
A large number of exhibitions continues to attest to Enrico Castellani's status in the international art world. In 1964 Enrico Castellan's works were shown at the Venice Biennale in a separate room. In 1968 he took part in "documenta 4". Enrico Castellani has lived in Cellano, near Viterbo, since 1975.