His father's artistry as an inventor and his mother's love for music and literature undoubtedly fostered in Kainen an insatiable interest in art.

Even at age ten, Kainen was eager to study master works, including clippings of art reproductions from The Jewish Daily Forward in his scrapbooks.

In the meantime he took drawing classes at the Art Students League, where Kimon Nicolaides taught him to "trust in the freedom and sureness of his hand".

Though he had a deep interest and appreciation for the old masters during this period of his life, he quickly found the Pratt curriculum backward, too anti-modernist, and dogmatic.

Upon entering school his portraits and color choices remained warm in tone, but as he progressed they became brighter and more reminiscent of Cézanne's palette.

The group had "three goals: they sought to represent the rawest human emotions, to use paint expressively rather than descriptively, and to focus on internal experience rather than external facts".

Kainen and Arshile Gorky became acquainted during a particular exchange in which they both defended the importance of copying master works and admitted to lurking in museums.

Kainen was an active participant in the WPA's graphic arts program during the second half of the decade, but he eventually parted with the aesthetics of social realism in favor of abstraction.

Though jarred by the elementary state of Washington's then slow-paced art scene, Kainen found inspiration in the Victorian skyline and architecture that defined the buildings surrounding his studio in Dupont Circle.

During the 1930s, and the time spent in New York after his expulsion from Pratt, Kainen had written art reviews for the Daily Worker and signed legal petitions that attempted to institute social change.