Pedersen and Else Alfelt were founder members of the CoBrA movement in 1948 together with Asger Jorn, Karel Appel and others. The movement took its name from the European cities where its founders were based: Copenhagen, Brussels and Amsterdam. They remained with the group until it dissolved in 1951, producing free-form, spontaneous images in strong, fantastic colours. He won the Eckersberg Award in 1950 and the Guggenheim Award in 1958. A retrospective was put on at the Carnegie Institute in Pittsburgh in 1961, and he was Denmark's representative at the Venice Biennale in 1962. He won the Thorvaldsen Medal in 1963.