Abstract expressionism is a post– World War II art movement in American painting, developed in New York in the 1940s. It was the first specifically American movement to achieve international influence and put New York City at the center of the western art world, a role formerly filled by Paris.n the years after World War II, a group of New York artists started one of the first true schools of artists in America, bringing about a new era in American artwork: Abstract Expressionism.