Kline studied at Boston University (1931–35) and at the Heatherley School of Art, London (1937–38), settling in New York City in the latter year. He was originally a representational painter, working in a style that merged Cubism and social realism. But in 1949, after viewing some of his black-and-white sketches enlarged by a projector, he realized their potential impact as large, abstract compositions. He began immediately to develop a highly personal form of Abstract Expressionism, a style of art based on the more or less spontaneous expression in abstract design of the artist's psychic states. Within a phenomenally short period of time, he mastered the new style, producing such masterpieces as Nijinsky (Petrushka) (c. 1950) almost immediately. Using inexpensive commercial paints and large house painter's brushes, he built graphic networks of rough but controlled bars of black paint on white backgrounds, creating positive shapes with the white areas as well as with the black strokes. Paintings such as Mahoning (1956) are characteristically of such large dimensions that the total effect is one of majesty and power. In the late 1950s Kline introduced colour into his paintings. Before his death, his work assumed a new direction in the extreme simplicity and elegance of huge, carefully balanced masses.