Here, Eastman conducted picture planning for animated sequences in orientation and training films, and he also wrote scripts and drew storyboards for the Private Snafu series for Army-Navy Screen Magazine.

Eastman and Bill Scott co-wrote the screenplay for the animated comedy Gerald McBoing-Boing, which won an Academy Award for Short Subject, Cartoons, in 1950.

Eastman also directed educational films and worked on the Flight Safety series for the United States Navy's Bureau of Aeronautics while at UPA.

[1] Eastman, a protégé and colleague of Theodor Geisel (pen name Dr. Seuss), wrote many books for children in his own distinct style.

Eastman was a member of the American Civil Liberties Union, Westport Artists, the Screen Cartoonists Guild, and the Audubon Society.