Picasso's always been such a huge influence that I thought when I started the cartoon paintings that I was getting away from Picasso, and even my cartoons of Picasso were done almost to rid myself of his influence.

He became a leading figure in the new art movement. For Head of Girl (1964) and Head with Red Shadow (1965) he collaborated with a ceramicist who sculpted the form of the head out of clay. In 1967 his first museum retrospective exhibition was held at the Pasadena Art Museum in California.

During the 1960s his paintings were exhibited at the Leo Castelli Gallery in New York City and along with Andy Warhol Jasper Johns James Rosenquist and others. He described pop art as "not 'American' painting but actually industrial painting". His work defined the basic premise of pop art better than any other through parody.