Butler was born in 1913 in Buntingford in Hertfordshire. He began his career as an architect but in 1936 became a blacksmith and eight years later began to sculpt, making constructions with steel and iron influenced by Gonzalez and Calder. With a natural talent for sculpture, in 1949 he had his first one-man exhibition at the Hanover Gallery in London, which exhibited the leading contemporary sculptors including Giacometti, Moore, and Marini.
Butler took part in many international exhibitions including the Venice Biennale, representing Britain in 1952 and 1954, where he was considered one of the most promising British sculptors of a generation that included Lynn Chadwick and Kenneth Armitage. Along with these artists he was commissioned to create a sculpture for the Festival of Britain in 1951. In 1953 he won first prize in an international competition for a monument to the Unknown Political Prisoner, the working model of which is in the Tate Gallery.
In the mid fifties Butler returned to a more directly figurative style, concentrating on bronze female nude figures and became a leading figure of sculpture in the post war period. A retrospective of his work was held at the Tate Gallery in 1983. His work is held in numerous international public collections including Tate Gallery, British Museum, Peggy Guggenheim Collection and Museum of Modern Art New York.