Many Disney-trained artists found work during this period on war-related, animated propaganda and training films. Some of the people who eventually defined the UPA style, including John Hubley, worked on such films, in which they experimented with contemporary graphics that would have been unwelcome at Disney's. In 1943, Bosustow, Hilberman, and Schwartz formed Industrial Film and Poster Service, the earliest incarnation of what became UPA. One year later, the United Auto Workers (UAW) hired them to make a film to endorse President Franklin Delano Roosevelt's re-election. Hell-Bent for Election was designed by Zachary Schwartz and directed by Charles M. Jones. Another film for the UAW, Brotherhood of Man, followed in 1945, directed by Robert Cannon.

In 1946, Hilberman and Schwartz decided to leave the company, now known as United Productions of America, and they sold their interest to Stephen Bosustow. With the war over, demand for propaganda and training films diminished; UPA's prospects were uncertain. At the same time, Columbia Pictures was unhappy with the cartoon shorts produced by its Screen Gems studio and was looking for a replacement. In 1948, Bosustow made a deal with Columbia. UPA would now produce entertainment cartoons for the general public.